Bulletin No. 40.— W, B. No. 471. Issued March 4, 1912, 

U.S. DEPARTMENT OF AGRICULTURE, 

1227 WEATHER, BUREAU. 

,03 S5 
[Copy 1 

BETWEEN THE PRECIPITATION 
OYER THE WATERSHED 0E THE OHIO RIVER 

r E AND THE, STREAM-FLOW 

AT CINCINNATI. 



J. WARREN SMITH, 

PBOMESSQR OF METBOEOLOaY. 



Prepared under direction ol WILLIS L. MOORE, Chief U. S. Weather Bureau. 




WASHINGTON: 

GOVERNMENT PRINTING OPMOE. 

1913, 



Mon«'gia^ 



Bulletin No. 40.— W. B. No. 471. 



Issued March 4, 1912. 



U. S. DEPARTMENT OF AGRICULTURE, 

: WEATHER BUREAU. 



THE RELATION BETWEEN THE PRECIPITATION 

OVER THE WATERSHED OF THE OHIO RIVER 

ABOVE AND THE STREAM-FLOW 

AT CINCINNATI. 



J. WARREN SMITH, 

PROFESSOR OP METEOROLOGY. 



Prepared under direction of WILLIS L. MOORE, Chief U. S. Weather Bureau. 




WASHINGTON: 

GOVERNMENT PRINTING OFFICE 

1912. 






rpHIS PUBLICATION may be pro- 

-*- cured from the Superintendent of 

Documents, Government Printing Office 

Washington, D. C, at 15 cents per copy 




JUi 



n? % 



LETTER OF TRANSMITTAL. 



United States Department of Agriculture, 

Weather Bureau, Office of the Chief, 

Washington, D. C, September 20, 1911. 
The Secretary of Agriculture, 

Washington, D. C. 
Sir: I have the honor to transmit herewith a paper by Prof. 
J. Warren Smith, of the Weather Bureau, on the Stream Flow of the 
Ohio River at Cincinnati and Precipitation, and to recommend 
its publication as a Weather Bureau bulletin, the edition to consist 
of 2,500 copies. 

Very respectfully, 

Willis L. Moore, 
Chief United States Weather Bureau. 
Approved. 

James Wilson, 

Secretary of Agriculture. 
(3) 



Digitized by the Internet Archive 
in 2011 with funding from 
The Library of Congress 



http://www.archive.org/details/relationbetweenpOOsmit 



STREAM-FLOW OF THE OHIO RIVER AT CINCINNATI AND 
PRECIPITATION IN THE WATERSHED ABOVE CINCINNATI. 



INTRODUCTION. 

In the following paper the relation between the precipitation 
over the Ohio watershed above Cincinnati and the stream-flow in 
the Ohio River at Cincinnati is discussed. 

The period covered is for 50 years, from 1861 to 1910, inclusive. 
The data are tabulated for each month of each year, for each month 
of 10-year and 25-year groups of years, and for combinations of 
months for each year of the entire period. 

The precipitation data considered were obtained from seven sta- 
tions in the Ohio River watershed above Cincinnati, the period of 
observations covering the 50 years from 1861 to 1910, inclusive. 
The data are complete for the 50 years at Cincinnati, Marietta, and 
Portsmouth, Ohio. At Lexington, Ky., the records extend from 
1861 to 1876 and from 1887 to 1910, all inclusive, while from 1882 
to 1886, inclusive, the records at Frankfort, Ky., were used. The 
record at Pittsburgh, Pa., extends from 1861 to 1866, and from 1872 
to 1910, all inclusive, while from 1867 to 1871, inclusive, data from 
Canonsburg, Pa., were used. The data at Westerville, Ohio, were 
complete from 1861 to 1901, inclusive, while from 1902 to 1910, 
inclusive, those for the Ohio State University were used. In the 
place of North Lewisburg, Ohio, the data for Urbana, Ohio, were 
used for the years 1909 and 1910. In each instance where data 
from two stations were used, the places were not far apart, and there 
is probably no great difference in the precipitation. 

It is unfortunate that there are no stations with long records in 
West Virginia or at other points south of the Ohio River. It is quite 
probable that the means obtained from the seven stations used do 
not always give the true average precipitation for the Ohio watershed 
above Cincinnati. Still, it was thought better to use the same 
stations running through the 50-year period than to consider data 
from other sources. 

Chart No. 1 indicates the locations of the stations. 

For the stream-flow data, instead of considering the average 
height of the water, we have tabulated the total number of days 
in each month when the river was between each 10-foot stage. 

(5) 



6 

Inasmuch as navigation is satisfactory in the Ohio when the river 
at Cincinnati is between 10 and 40 feet, we have considered the low- 
water days as those below 10 feet, and the high- water days as those 
above 40 feet. 

The flood stage is 50 feet at Cincinnati, but there is more or less 
trouble in navigating the stream when the river is above 40 feet 
because of strong currents, swirls, debris, and, in its season, ice. 

The work of tabulation has been great, and we have tried to group 
the data in every possible way to show the relation of the factors 
under consideration. An effort has been made to make the study 
exhaustive, plain, and convincing. 

It seems to the writer that the statements made in the conclusions 
following are proven beyond dispute, and that the question of 
increasing flood conditions and increasing low-water periods is fairly 
settled in the negative, so far as our available stream-flow data can 
settle it. 

CONCLUSIONS. 

1. River stages at Cincinnati depend upon the precipitation over 
the whole watershed above that city. 

2. There has been a very slight decrease in flood days in recent 
years, with the same rainfall. 

3. The same amount of rainfall causes a better flow of water in the 
river during the low-water period than formerly. The number of 
low-water days was 14 per cent less during the past 25 years than 
during the preceding 25, calculating for the same rainfall. During 
the 10 years ending with 1910 the tendency for low water, with an 
equivalent rainfall, was not so great as for any preceding 10-year 
period for the past 50 years. 

4. Floods do not occur at Cincinnati during February and March 
unless the precipitation for these months is in excess of the normal, 
except on very rare occasions. The number of flood days increase 
most rapidly when the precipitation during these months is about 3 
inches above the normal or about one-half more than the normal . 

EXPLANATION AND DISCUSSION OF TABLES. 

Table No. 1. 

In this table there is given for each month of each year from 1861 
to 1910, inclusive, the total number of days that the river at Cin- 
cinnati, Ohio, was below 5 feet, between 5 and 5.9 feet, 10 and 19.9 
feet, 20 and 29.9 feet, 30 and 39.9 feet, etc., up to the highest water 
recorded. 

These figures were obtained from the published daily river reading 
tables. By an inspection of the table the high and low water months 
can be quickly determined. 



For example, in January, 1897, the water did not go above 20 feet 
during the month, the only January in the 50 years when this was 
true. On the other hand, the river reading was at no time below 
20 feet in January, 1870, 1882, 1889, 1891, and 1907. The river has 
been above 60 feet on only 6 days in January, and this in 1907. 

There are some interesting periodicities or combinations indicated. 
For example, there seemed to be increasing flood conditions in Feb- 
ruary, 1881 to 1884, and again from February, 1888 to 1891, but in 
the succeeding years the river was back to below normal height. 

The river did not go above 20 feet in June frOm 1871 to 1879, inclu- 
sive. September seems to be a month of extremes; on a few years 
the river has not gone above 5 feet during the entire month, and in 
2 cases the readings were all above 10 feet. 

Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910. 



Years. 


to 
4.9 feet. 


5 to 
9.9 feet. 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 60 to 
59.9 | 69.9 
feet. feet. 


70 to 
79.9 
feet. 


JANUARY. ; D 
1861 -- 


Days. 


Days. 

15 

12 

15 

16 

8 

9 

26 

16 

7 


Days. 

8 

6 

4 

9 

14 

14 

5 

6 

9 

15 

4 

5 

17 

10 


Days. 
6 
3 
11 


Days. 
2 
4 
1 


Days. 


Days. Days. 


1862 






6 




1863 . . . 








1864 




6 






1865 




9 
8 






1866 












1867 












1868 






6 

15 

6 

3 


3 








1869 












1870 






4 6 




1871 




14 
11 


10 
15 
10 

5 
18 

7 
13 
10 
13 

1 

8 






1872 










1873 




4 
10 








1874 






6 








1875 




5 


4 4 








1876 




9 

4 

17 

6 

19 

13 

2 

9 

13 

12 

17 

9 

9 

26 

9 

17 

13 

2 

2 

10 

8 


4 
5 


10 






1877 






4 


5 






1878 




4 






1879 




12 
8 
.5 
6 
2 
8 
3 
5 
2 
6 
5 

14 
8 
4 










1880 






3 








1881 




5 








1882 




23 








1883 






20 
10 
11 
9 
17 
12 








1884 














1885 






5 








1886 












1887 






3 








1888 




4 








1889 












1890 






2 


6 
6 
2 








1891 












1892 






12 

24 

29 

1 

12 

30 

9 

2 

9 

20 
14 
12 
21 
25 
5 








1893 




5 








1894 















1895 






5 

11 

1 


10 


5 








1896 











1897 














1898 




12 

10 
7 
4 

13 
4 
5 

17 
3 

17 
9 


6 
9 
5 


11 
8 


5 






1899 










1900 




4 
6 








1901 












1902 




5 


o 








1903 




6 
2 










1904 









4 








1905 




1 










1906 




9 
9 










1907 






S 


5 


6 




1908 






14 

21 

5 






1909 




1 
o 










1910 




9 


s 









Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, ivas between the heights indicated, 1861 to 1910 — Continued. 



Years. 


Oto 
4.9 feet. 


5 to 
9.9 feet 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 
feet. 


FEBRUARY. 
1861 


Days. 


Bays. 


Bays. 
7 
3 


Bays. 
11 

4 


Bays. 
10. 
11 
16 


Bays. 


Bays. 


Bays. 


Bays. 


1802 






10 
1 








1863 






1 10 

11 : 11 

12 | 13 

13 11 








1864 




7 








1865 




1 
4 
6 


2 








1866 












1867 






2 1 5 
23 3 


8 


7 






1868 




3 






1869 




4 
10 

7 
17 


21 
10 
19 
3 
7 

10 
7 
7 
6 
23 
17 
7 
5 
4 
5 
2 
7 
14 


3 

8 
2 










1870 














1871 














1872 




9 










1873 






6 

7 
16 

3 
18 

3 


12 
6 
1 
9 
3 
2 
5 
3 
7 
4 
5 
2 


3 

5 








1874 












1875 




4 








1876 




10 








1877 




1 








1878 












1879 






4 
12 

7 


2 
3 

7 
11 
2 
6 








1880 






4 
2 
9 
9 
6 






1881 










1882 










1883 








7 
11 




1884 








2 


1885 




4 


17 
5 




1886 




8 


1 

18 








1887 






10 






1888 




3 


8 
12 


18 
9 
3 








1889 




7 
12 
2 










1890 






10 

18 


3 

8 






1891 












1892 






7 


22 

4 

12 






1893 






10 
11 


6 


8 






1894. . . 






5 
28 
11 
4 
9 
9 
8 
23 
9 






1895 














1896 




'• 


13 
5 
7 
7 

12 
1 
5 
4 

11 

12 
4 

14 

12 
5 

12 

21 
7 
5 

18 
2 

11 
3 
9 

14 

26 

26 
2 

11 


5 

7 

12 

12 

8 










1897 






6 


4 


2 




1898 








1899 ■.. 














1900 














1901 




4 
8 










1902 




4 
10 
2 

4 


2 
14 








1903 










1904 






16 
5 
21 
11 
3 
9 
7 

10 








1905 




7 
3 










1906 












1907 




3 

5 

9 
8 










1908 






7 
1 

1 


2 
4 






1909 










1910 










MARCH. 

1861 








* 




1862 






18 
23 


6 
3 








1863 














1864 






13 








1865 






10 
18 
9 
10 
8 
3 
5 


14 


5 






1866 






2 






1867 






7 
10 
2 
2 


12 






1868 






2 

7 






1869 












1870 












1871 












1872 




5 


24 
16 

7 










1873 




4 










1874 






16 ; 8 

5 21 
11 8 
7 13 










1875 






5 
1 
3 








1876 






11 

7 
7 








1877 




1 








1878 




18 
11 
15 
26 
10 
13 
5 
S 


6 
20 

9 

5 
15 
18 

8 








1879 














1880 








7 






1881 














1882 








6 








1883 














1884 






3 

19 


15 
1 








1885 i 


4 









Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910 — Continued. 



v™™ to 
Years. ; 4.9 feet. 


5 to 

9.9 feet. 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 
feet. 


march— continued. i j) ays- 
1886 


Days. 


Days. 
18 
12 
13 
14 


Days. 
7 
4 
12 
17 
3 


Days. 
5 
8 
6 


Days. 
1 
4 


Days. 


Days. 


Days. 


1887 . . ' 




3 






1888 










1889 














1890 






4 
21 

8 

7 


12 

10 


12 






1891 












1892 






4 
2 
8 
3 
17 


19 
22 
23 
17 
3 








1893 














1894 














1895 








11 

11 

17 

2 

13 

14 

7 

8 

9 

5 

5 

11 

2 

10 

9 

3 

6 
6 
3 
7 

11 
9 
5 

12 
4 
7 











1896 














1897 






i2 

3 

6 


2 
5 

7 






1898 






13 


6 

5 
16 
15 
4 
3 
11 
12 
13 
14 
2 
8 
4 

12 

9 
15 
22 

8 
19 
25 
12 
20 
10 
12 

3 
11 

6 
12 
19 
17 

2 
10 
12 
18 

8 

8 
13 
14 

4 

4 
12 

8 
12 

8 
16 
17 
15 
14 

8 
14 
17 
12 

7 

8 
14 
11 

8 
11 
15 
29 
10 
21 

6 


2 




1899 








1900 






1 
2 

4 






1901 




7 










1902 




11 
11 
14 
11 
1 
4 
13 
6 
9 

7 
9 


4 

8 






1903 : . - 1 








1904 




1 
3 
6 






1905 










1906 










1907 






7 
6 
2 
3 


4 




1908 










1909 






6 
12 

a 






1910 . 










APRIL. 
1861 










1862 






6 






1863 






12 
1 
5 
2 






1864 














1865 






6 








1866 












1867 














1868 






4 


2 
6 
13 








1869 












1870 














1871 






18 
8 
4 
4 
11 
6 
9 
28 
15 
13 








1872 




4 


10 
15 
14 
7 
4 
4 


5 








1873 










1874 






6 








1875 












1876 






1 








1877 












1878 














1879 






5 
2 
9 










1880 






3 
3 








1881 












1882 1 






22 








1883 






13 

8 

10 

2 

4 

7 


9 








1884 






9 

5 

8 

17 

11 

22 

1 

5 








1S85 




1 










1886 




4 
5 


12 






1887 










1888 












1889 1- - 








* 




1890 






16 
11 
8 

7 


1 
6 
6 
1 








1891 












1892 












1893 






5 
15 

7 
13 

5 

6 
10 
23 








1894 












1895... . 






9 
3 
11 
2 
4 










1896 






6 







1897 










1898 






2 
2 


3 
2 




1899 








1900 









1901 






12 
5 

14 
6 
1 
3 
1 

11 
5 


2 
3 
5 
5 


8 




1902 






8 






1903 












1904 






11 








1905 






18 
6 








1906 






5 


1 






1907 










1908 






5 


4 






1909 






4 
24 






1910 















21464—12- 



10 

Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910 — Continued. 



Years. 


Oto 
4.9 feet. 


5 to 
9.9 feet, 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
t.,9.9 
feet. 


70 to 
79.9 
feet. 


MAT. 
1861 


Days. 


Days. 


Days. 
10 
22 
16 
15 

5 
22 
11 

6 
12 
28 
11 
23 
10 
12 
21 
23 
21 

9 
21 
11 
21 

1 
17 
25 
30 
17 
10 
26 
25 


Days. 
14 

7 
11 
10 

9 

4 
17 
10 
14 

3 
10 


Days. 

7 
2 


Days. 


Days. 


Days. 


Days. 


1862 














1863 




4 










1864 




6 
9 










1865 






6 


2 






1866 




5 






1867 




3 
13 

5 










1868 






2 








1869 












1870 














1871 




3 

8 


6 


1 








1872 










1873 




12 
5 

4 

8 

10 

21 


9 
3 










1874 




7 
6 


4 






1875 1 








1876 ! 












1877 














t878 




1 










1879 ! 


10 
12 
2 










$880 


4 

8 

13 

14 

6 

1 

6 

14 


2 


2 






1881 .' 


i 




1882 


13 


4 






1883 . . . 








1884 












1885 












1886 ' 




8 
4 








1887 


3 
5 








1888 




1 




1889 


6 
10 










1890 




14 


7' 






1891 


20 


11 
5 
1 

22 
31 
21 
11 
2 
20 
25 
12 
27 
16 
17 
15 
22 
10 






1892 1 


20 

10 

4 


6 
9 
3 










1893 




9 


2 






1894 




2 






1895 












1896 




10 














1897 ...: 




16 
29 
11 


4 










1898 














1899 
















1900 




6 












1901 




9 


7 


2 


1 






1902. . . 




4 
12 






1903 




3 
9 
7 
2 
20 
19 
11 
12 

4 
6 












1904 




5 
3 










1905 : 






6 








1906.. .... 


7 








1907 | 


1 
6 

4 










1908 | 




6 

7 








1909 




9 
19 

14 
24 








1910 












JUNE. 

1861 




12 












1862 














1863 


6 


24 
11 












1864 


19 
28 














1865 




2 












1866 


2 


28 
1 
3 












1867 


21 
20 
18 
23 

3 
18 

7 


8 
7 
12 
5 












1868 














1869 














1870 




2 
27 
12 
23 
30 

4 
15 
10 

9 
25 

5 

8 












1871 . ..... 














1872 
















1873 
















1874 
















1875 




26 
15 
20 
21 

5 
20 
15 
10 
13 

8 
22 














1876 
















1877 
















1878 
















1879 
















1880 




5 
4 
10 
14 
22 
4 












1881 




3 

10 
3 








1882 










1883.' 












1884 












3885 




4 






| 





11 

Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910 — Continued. 



Years. 


Oto 
4.9 feet. 


5 to 
9.9 feet. 


10 to 
19.9 

feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 
feet. 


JUNE — continued . 
1886 


Days. 


Bays. 
2 
9 
19 


Days. 
24 
15 
11 

5 
24 
18 
13 
26 
18 

1 
21 
23 
21 
30 
14 

4 
14 
30 
16 
24 
27 

7 
26 
16 
11 


Days. 
4 
6 


Days. 


Days. 


Days. 


Days. 


Days. 


1887 . 














1888 














1889 




20 
4 
12 
13 
4 
1 


5 
2 










1890 














1891 














1892 






4 










1893 














1894 




11 
24 
6 
6 
9 












1895 


5 












1896 


3 

1 












1897 














1898 














1899 
















1900 




16 














1901 




15 
1 


9 


2 








1902 




15 








1903 














1904 




4 


10 
6 












1905 














1906 




3 












1907 




13 


7 


3 








1908 




4 








1909 




14 
17 












1910 






2 










JULY. 
1861 




31 
8 
24 
13 
9 
18 
28 
31 










1862 




23 

7 














1863 
















1864 


18 














1865 


21 

10 

3 


1 
3 












1866 














1867 














1868 
















1869 




16 
14 


15 












1870 




17 
31 
11 
6 
19 












1871 
















1872 




20 
23 

2 
13 
23 
20 

9 














1873 




2 












1874 


10 












1875 


4 


14 










1876 




8 
11 
22 
23 

14 
25 
2 
2 
17 
27 
6 
23 
12 










1S77 
















187S 
















1879 - 


8 














1880 


17 
6 
18 
29 
13 
2 
21 














1881 
















1882 




11 


























1884 


1 

2 














1885 














1886 


4 












1887 


8 












1888 


12 
21 
13 
28 
21 
10 


5 
10 


2 










1889 












1890 




18 
3 

10 
21 
16 
24 
1 
6 
25 
26 
22 
4 












1891 
















1892. 
















1893 
















1894 . 


15 
4 














1895 


3 

14 
19 
6 
5 
9 
25 
16 
29 
19 
28 
14 
20 
12 
21 
20 














1896 


10 
6 


4 


2 








1897 










1898 














1899 
















1900 
















1901 




2 
15 












1902 














1903 




2 

8 












1904 




4 
3 












1905 














1906 




17 












1907 




11 












1908 




19 
9 
5 












1909 




1 

G 












1910 















12 

Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910 — Continued. 



Years. 


Oto 

4.9 feet. 


5 to 
9.9 feet. 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


.30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 

feet. 


AUGUST. 
1861 


Days. 


Days. 
11 
16 
26 

3 
13 
20 
30 
21 
22 

9 
19 
23 
12 
24 

1 
IS 
14 
17 
18 
21 
18 
11 
20 
18 

3 
14 
12 
20 
10 
21 
12 
28 
15 

1 
31 


Days. 
20 


Days. 


Days. 


Days. 


Days. 


Days. 


Days. 


1862 


15 

5 
18 










1863 












1864 


10 
18 
9 










1865 ' 














1866 


2 
1 














1867 














1868 


10 
9 
22 














1869 
















1870 ■-.- 














1871 


12 














1872 


8 
19 

7 

16 
13 














1873 
















1874 
















1875 




.3 2 


4 


5 






1876... 








1877 


17 












1878 


14 
13 
10 












1879 












1880 




, 








1881 


13 










1882. . . 


19 
10 
4 
28 
17 


1 










1883 


1 
9 












1884 














18S5... 














1880 
















1887 


19 














1888 


5 
21 

S 
19 

3 


3 


3 










1889... 












1890 




2 












1891 . . . 














1892 
















1893 


16 
30 














1894 
















1895 
















1890 




21 
11 
18 
7 
5 

17 
13 


3 


5 


2 








1897 




20 








189S... 




8 


5 










1899.. 


5 
2 


19 

24 

14 

18 

31 

31 

3 

5 

5 

24 

19 

14 

22 










1900 . . . 














1901 . 














1902... 
















1903.... 
















1904 . . . 


















1905 . . 




28 
24 
22 
7 
12 














1906 . . . 




2 
4 












1907 














1908... 














1909... 














1910... 


17 

30 
30 














SEPTEMBER. 
1861 


7 


1 












1862 . . . 












1863 . 


















1864... 


3 

8 

7 

8 

10 

19 

20 

15 

16 

14 

8 

12 

12 

23 

18 

16 

25 

6 


27 
18 
12 














1865 . . . 


22 


4 
4 












1866 


5 


2 








1867... 








1868 . 


7 
7 
4 


8 
4 


3 


2 








1809 










1870 . . . 


6 
15 
14 
11 
22 
18 










1871 














1872 . 
















1873' . 


5 














1874... 














1875... 
















1876 . . . 


6 


9 


3 










1877... 


7 










1878 .. 


5 
6 


3 


4 










1879 


8 

5 

24 










1880 . . . 














1881.. 
















1882 


30 














1883 


29 
30 


1 














1884 














1885 


12 


18 













13 

Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910 — Continued. 



Years. 


to 
4.9 feet. 


5 to 
9.9 feet. 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 
feet. 


September— continued . 
1886 


Bays. 
11 
30 


Days. 
19 


Days. . 


Days. 


Days. 


Days. 


Days. 


Days. 


Days. 


1887. . 
















1S8S 


2 
28 


24 
2 
15 
13 


4 












1889. 














1890 




10 


5 










1891 




17 
27 
20 

2 
14 
30 
13 
29 
16 
13 
12 

3 
22 
12 
14 
16 

1 

5 
30 
26 










1892 


3 

5 

24 
16 














1893 


5 
4 














1894 




























1896 
















1897 


17 
















1898 


1 














1899 . 


14 
17 














1900 
















1901 


18 














1902 


1.27 














1903 


8 














1904 


[18 














1905 


16 
14 

29 














1906 
















1907 
















1908 


25 














1909 
















1910 


3 


1 

17 














OCTOBER. 
1861 


9 


3 


2 








1862 


31 
25 










1863 


6 
9 

25 
5 
















1864 


18 
6 
17 


4 












1865 














1866 




6 


3 










1867 


31 










1868 


20 
24 
25 


7 
7 


3 


1 










1869 












1870 


6 
31 
24 
23 
16 














1871 
















1872 


7 
1 
15 
31 
16 
16 
10 
















1873 


3 


4 












1874 












1875 
















1876 


1 
15 
16 
31 
20 
26 


14 














1877 














1878 


5 














1879 














1880.. 


11 
5 

21 

24 
3 
6 

14 
















1881 
















1882 


10 

7 














1883 
















18S4 


28 
11 
17 
31 
















14 














188.6 














1887 
















1888 


11 
24 


5 

7 
15 


11 


4 










1889 












1890 




12 


4 










1891 


18 
28 


13 
3 

15 
8 










1892 
















1893 


16 














1894.. 


23 
31 












1895 















1896 


2 


25 


4 












1897 


31 

4 

31 

27 

3 

3 

10 

31 












1898 


18 


4 


"5" 












1899 












1900 


3 

28 
24 

17 


1 












1901 














1902 


4 
4 




























1904 














1905 


19 


11 
31 

13 


1 










1906 
















1907 




18 
4 












1908 


27 
15 
7 












1909 


15 


1 












1910 


17 ; 7 













14 

Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, was between the heights indicated, 1861 to 1910 — Continued. 



Years. 


Oto 
4.9 feet. 


oto 
9.9 feet. 


10 to 
19.9 
feet. 


20 to 
29.9 
feet. 


30 to 
39.9 

feet. 


40 to 
49.9 
feet. 


50 to 
59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 
feet. 


NOVEMBER. 

1861 


Days. 


Bays. 


Days. 
13 
3 
8 
8 
14 
12 


Days. 
16 


Days. 

1 


Days. 


Days. 


Days. 


Days. 


1862 


19 


8 
22 

2 
16 

1 
19 

5 
23 
25 

4 
17 

4 










1863 














1864 




20 












1865 














1866 




17 












1867 


11 












1868 


25 
7 
5 
6 
13 
18 














1869 
















1870 
















1871 


20 














1872 














1873 




8 












1874.. 


26 


1 3 












1875 


6 
8 

16 
4 
5 

14 
6 

30 


19 
22 
10 
21 
5 
16 
18 


5 












1876... 














1877 




1 
3 


3 
2 










1878 












1879 


20 










1880 














1881 




6 












1882 














1883 




26 


4 












1884 


24 


6 












1885 


29 
5 


1 

7 












1886 


13 


4 


1 










1887 


28 










1888 






3 

11 
8 
5 


17 
10 
18 
4 


10 
9 

4 










1889 














1890 














1891 


2 
11 


19 

19 
18 
23 
4 
1 
11 










1892 












1893 


12 














1894 . . . 


7 
26 














1895 
















1896 


■ 27 
11 
22 


2 












1897 


8 












1898 


8 












1899 


8 

6 

20 

3 

11 

25 


22 
17 

9 
24 
12 

5 












1900 


3 

1 
3 

. 7 


1 


3 










1901 










1902 














1903 . . . 














1904 














1905 


29 
13 
17 


1 

5 

11 












1906... 




8 
2 
9 
29 
26 


4 










1907 












1908 


21 












1909 . 


1 














1910 


4 














DECEMBER. 

1861 


22 

8 
19 
12 
10 

3 
10 
18 

8 
30 

6 
11 

5 
27 
10 
24 
25 

6 
15 
18 
15 
25 
23 
17 
22 


5 


4 










1862 




23 
6 










1863 




6 

11 

1 

19 

4 
13 
12 












1864... 




3 

7 
9 
2 


5 
2 








1865 




11 








1866 










1867 


8 


7 










1868... 










1869 . . . 






11 










1870... 




1 
24 
19 










1871 . . 


1 














1872 


1 
14 

1 
16 












1873 




8 


4 








1874 




3 








1875 




1 


4 








1876... 




7- 








1877 . . . 




6 
11 
2 
3 
1 












1878 . 






11 
5 
7 

13 


3 

2 








1879 . . . 




7 
3 








1880 










1881 




2 








1882 




6 








1883 




1 
2 

8 


1 


6 









1884 . . . 


4 



8 






1885 


1 




! 





15 



Table 1. — Number of days during each month and year when the river reading at Cincin- 
nati, Ohio, loas between the heights indicated, 1861 to 1910 — Continued. 



Years. 


Oto 
4.9 feet. 


5 to 
9.9 feet. 


10 to 
19.9 

feet. 


20 to 
29.9 
feet. 


30 to 
39.9 
feet. 


40 to 
49.9 

feet. 


50 to 

59.9 
feet. 


60 to 
69.9 
feet. 


70 to 
79.9 
feet. 


decem b er— continued . 
1886 


Days. 


Days. 


Days. 
15 


Days. 
16 


Days. 


Days. 


Days. 


Days. 


Days. 


1887 


4 


27 














1888 


26 
4 
24 
21 
13 
22 
20 
7 

16 

23 

22 

9 

8 

20 

12 

9 

1 

7 

13 

15 

5 

8 

13 


5 
27 











1889 
















1890 






5 

10 


2 










1891 














1892 




18 

2 

11 

22 












1893 ... 




7 












1894 














1895 


1 


1 

15 
8 
6 
7 

10 
4 

10 
1 












1896 












1897 
















1898 






3 










1899 


15 
9 










1900 


3 

7 
2 


1 








1901 i 








1902 




7 








1903 


21 
6 








1904 ; 24 












1905 - 


16 
9 
12 


7 

9 

' 4 


1 








1906 












1907 














1908 


12 


14 
23 
16 










1909 














1910 : 


2 

























Table No. 2. 

This table gives the average precipitation for the watershed for 
each month, together with the averages for each 10 years, for each 
25 years, and for the whole 50 years. 

Table 2. — Average j)recipitation in the Ohio watershed above Cincinnati, 1861 to 1910, 

inclusive. 



Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct, 


Nov. 


Dec. 


An- 
nual. 


1861 


In. 
2.5 
5.4 
6.2 
1.8 
2.6 
3.5 
2.4 
3.1 
2.9 
6.2 
2.1 
0.9 
2.5 
4.2 
1.7 
6.1 
2.9 
3.0 
3.0 
4.3 
2.9 
5.9 
2.9 
3.8 
5.3 
3.7 
2.7 
4.7 
3.8 


In. 
2.0 
3.1 
3.5 
1.4 
2.4 
2.5 
5.0 
1.2 
2.9 
3.1 
2.7 
1.9 
3.6 
4.1 
1.8 
2.5 
0.7 
1.7 
2.8 
4.2 
3.4 
5.3 
7.3 
6.1 
2.3 
1.8 
7.3 
1.8 
1.6 


In. 
2.3 
4.6 
3.6 
2.6 
5.0 
3.7 
5.0 
5.3 
4.2 
4.2 
2.6 
1.5 
3.1 
3.5 
4.0 
3.8 
5.3 
3.0 
4.3 
3.8 
3.8 
4.8 
2.9 
4.1 
1.0 
3.3 
.2.1 
4.3 
1.3 


In. 
4.5 
5.6 
2.0 
2.5 
4.5 
2.7 
2.7 
3.6 
2.9 
2.5 
2.0 
4.7 
2.9 
5.2 
1.7 
2.7 
2.7 
2.4 
1.0 
5.5 
2.4 
2.9 
4.2 
2.5 
3.6 
3.0 
5.1 
2.1 
2.0 


In. 
5.0 
3.2 
2.4 
3.2 
7.3 
1.3 
4.0 
5.5 
4.6 
1.9 
2.8 
2.9 
3.8 
1.3 
3.2 
2.6 
2.3 
2.6 
2.2 
3.2 
2.2 
7.7 
5.0 
4.0 
3.7 
5.0 
3.6 
3.7 
3.5 


In. 
3.5 
3.3 
2.7 
2.4 
4.3 
4.5 
3.2 
4.8 
3.9 
3.7 
3.3 
2.7 
3.5 
2.8 
5.0 
3.5 
5.6 
3.9 
4.3 
4.8 
4.4 
5.5 
4.6 
2.8 
3.6 
4.2 
3.5 
2.5 
3.9 


In. 
3.5 
3.6 
2.4 
1.5 
5.8 
5.5 
3.9 
3.1 
4.5 
4.4 
3.0 
6.2 
5.7 
5.1 
8.9 
7.0 
4.0 
4.2 
4.4 
2.9 
4.1 
3.0 
3.7 
3.0 
2.3 
3.4 
3.5 
5.2 
5.7 


In. 
4.5 
2.2 
2.9 
5.4 
3.8 
3.9 
2.8 
4.8 
2.2 
3.1 
4.4 
3.1 
3.8 
2.4 
3.1 
3.5 
1.8 
3.2 
6.1 
4.6 
1.6 
5.0 
1.6 
1.5 
5.8 
3.4 
2.4 
8.1 
1.3 


In. 
3.3 
1.1 
2.1 
4.9 
5.9 
10.1 
0.8 
7.6 
4.0 
1.4 
1.3 
1..6 
2.3 
2.7 
2.1 
5.6 
2.2 
4.2 
2.8 
2.6 
2.5 
3.3 
2.3 
3.9 
2.6 
3.6 
2.5 
2.1 
4.0 


In. 
3.6 
1.7 
3.7 
2.4 
1.5 
3.2 
3.0 
1.5 
2.0 
2.9 
1.8 
2.5 
4.5 
0.5 
2.6 
2.4 
1.9 
2.7 
0.8 
2.3 
4.7 
1.8 
5.4 
1.4 
3.6 
1.1 
0.5 
4.1 
2.1 


In. 
4.0 
2.9 
2.5 
4.4 
0.9 
4.1 
2.1 
2.0 
3.6 
1.8 
2.7 
1.0 
2.1 
3.9 
4.3 
2.4 
3.5 
3.2 
3.2 
3.0 
3.6 
1.6 
3.5 
1.4 
2.6 
4.6 
2.6 
4.5 
4.7 


In. 
1.2 
3.1 
3.2 
3.7 
4.8 
2.2 
4.2 
2.2 
3.1 
2.3 
2.6 
2.5 
5.0 
3.5 
3.6 
1.4 
2.4 
3.6 
4.7 
3.2 
5.0 
1.9 
4.5 
4.1 
1.8 
2.5 
2.7 
1.5 
2.5 


In. 
39.9 


1862 


39.8 


1863 


37.2 


1864 


36.2 


1865 


48.8 


1866 


47.2 


1867 


39.1 


1868 

1869 


44.7 
40.8 


1870 


37.5 


1871 


31.3 


1872 


31.5 


1873 


42.8 


1874 


39.2 


1875 

1876 


42.0 
43.5 


1877 

1878 


35.3 
37.7 


1879 


39.6 


1880 


44.4 


1881 


40.6 


1882 


48.7 


1883 


47.9 


1884 


38.6 


1885 


38.2 


1886 


39.6 


1887 


38.5 


1888 


44.6 


1889 


36.4 



16 

Table 2. — Average precipitation in the Ohio watershed above Cincinnati, 1861 to 1910, 

inclusive — Continued . 



Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


An- 
nual. 


1890 


In. 

5.3 

3.4 

2.4 

2.9 

2.5 

5.0 

1.6 

2.1 

6.7 

4.1 

2.5 

1.6 

2.4 

2.3 

2.6 

2.0- 

2.5 

7.4 

1.6 

1.2 

4.8 


In. 
5.9 
4.9 
3.1 
5.4 
3.7 
0.7 
2.6 
5.3 
2.1 
2.7 
3.2 
1.1 
1.1 
5.7 
2.1 
1.7 
1.6 
1.2 
4.6 
5.9 
4.3 


In. 
6.4 
5.1 
3.0 
2.0 
2.2 
2.4 
4.1 
6.0 
7.2 
5.7 
2.2 
2.6 
3.1 
4.2 
5.9 
3.5 
5.3 
5.8 
6.0 
3.0 
0.3 


In. 
3.3 
2.2 
4.3 
6.5 
3.0 
2.4 
1.9 
4.0 
2.3 
1.8 
1.8 
4.3 
2.2 
3.4 
2.9 
3.2 
1.6 
2.8 
4.1 
4.6 
2.9 


In. 
4.9 
2.2 
5.2 
4.4 
3.6 
2.1 
3.1 
3.9 
4.5 
4.2 
2.5 
3.7 
3.2 
2.6 
3.1 
6.0 
2.3 
3.3 
4.7 
4.2 
4.3 


In. 
4.5 
4.9 
4.8 
4.0 
3.0 
2.8 
4.3 
3.1 
3.9 
3.4 
2.7 
4.7 
6.8 
3.9 
3.2 
4.4 
4.1 
4.6 
2.3 
6.0 
3.2 


In. 
2.3 

4.8 
4.2 
3.0 
1.9 
2.2 
9.1 
5.5 
4.2 
3.6 
3.9 
2.4 
3.1 
3.2 
2.6 
3.4 
5.2 
6.1 
3.6 
4.1 
3.7 


In. 
5.1 
3.1 
3.0 
2.0 
2.8 
2.9 
3.7 
2.4 
4.2 
2.6 
3.9 
3.5 
1.7 
2.1 
2.2 
4.6 
4.5 
2.9 
2.8 
2.8 
2.1 


In. 
5.6 

1.8 
3.0 
2.2 
2.9 
l'l 
4.8 
1.0 
2.7 
2.7 
1.3 
2.3 
3.4 
1.2 
1.4 
3.2 
3.3 
2.6 
0.4 
2.0 
4.6 


In. 
3.9 
1.6 

0.5 
4.5 
1.5 
1.1 
1.8 
0.4 
4.0 
2.0 
1.6 
0.6 
2.4 
2.2 
1.1 
4.7 
2.1 
2.2 
1.1 
2.3 
3.7 


In. 
2.6 

4.8 
2.6 
2.3 
1.9 
3.8 
3.1 
6.3 
3.1 
1.9 
5.0 
1.4 
2.7 
2.1 
0.3 
2.7 
2.9 
2.1 
1.1 
1.6 
1.4 


In. 
3.5 
2.4 
2.0 

2.6 
3.4 
3.6 
1.7 
3.4 
2.7 
3.0 
1.7 
4.0 
4.8 
1.8 
3.3 
2.8 
3.9 
2.9 
2.0 
2.6 
2.7 


In. 
53.3 


1891 


41 2 


1892 


38.1 


1893 


41.8 


1894 


32 4 


1895 


30.1 


1896 


41.8 


1897 


43.4 


1898 


47 6 


1899 


37.7 


1900 


32 3 


1901 


32.2 


1902 


36.9 


1903 


34.7 


1904 


30.7 


1905 

1906 


42.2 
39.3 


1907 


43.9 


1908 

1909 


34.3 
40.3 


1910 


38.0 




3.40 


3.18 


3.78 


3.15 


3.63 


3.91 


4.11 


3.34 


2.98 


2.35 


2.85 


3.00 


39.68 






1861-1870 


3.66 
3.07 
4.10 
3.32 
2.84 


2.71 
2.60 
4.28 
3.37 
2.93 


4.05 
3.49 
3.40 
3.99 
3.97 


3.35 
3.08 
3.11 
3.02 
3.20 


3.84 
2.69 
4.33 
3.57 
3.74 


3.63 
3.94 
3.95 
3.69 
4.32 


3.82 
5.14 
3.62 
4.24 
3.74 


3.56 
3.60 
3.58 
3.06 
2.92 


4.12 
2.74 
3.24 
2.35 
2.44 


2.55 
2.20 
2.86 
1.90 
2.24 


2.83 
2.93 
3.17 
3.48 
1.83 


3.00 
3.25 
3.00 
2.65 
3.08 


41.12 


1871-1880 


38.73 


1881-1890 


42.64 


1891-1900 


38.64 


1901-1910 


37.25 






1861-1885 


3.52 
3.27 


3.10 
3.26 


3.68 
3.88 


3.20 
3.11 


3.52 
3.75 


3.86 
3.95 


4.23 
4.00 


3.48 
3.20 


3.33 
2.63 


2.58 
2.12 


2.81 
2.88 


3.19 
2.80 


40.50 


1886-1910 


38. 85 







Table No. 3. 

This table shows the departure of the monthly precipitation from 
the normal for each month and the departure of each 10-year and each 
25-year average from the normal. 

Table 3. — Departure of monthly precipitation from normals, Ohio watershed above 
Cincinnati, Ohio, 1861 to 1910, inclusive. 



Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 1 Jul y. 


Aug. Sept. 


Oct. 


Nov. 
In. 


Dec. 


An- 
nual. 




In. 


In. 


In. 


In. 


In. 


In. 


In. 


In. 


In. 


In. 


In. 


In. 


'1861 :. 


-0.9 


-1.2 


-1.5 


+1.3 


+1.4 


-0.4 


-0.6 


+1.2 


+0.3 


+1.2 


+1.2 


-1.8 


+ 0.2 


1862 


+2.0 


-0.1 


+0.8 


+2.4 


-0.4 


-0.6 


-0.5 


-1.1 


-1.9 


-0.7 


+0.1 


+0.1 


+ 0.1 


1863 


+2.8 


+0.3 


-0.2 


-1.2 


-1.2 


-1.2 


-1.7 


-0.4 


-0.9 


+1.3 


-0.3 


+0.2 


-2.5 


1864 


-1.6 


-1.8 


-1.2 


-0.7 


-0.4 


-1.5 


-2.6 


+2.1 


+1.9 


±0.0 


+1.6 


+0.7 


-3.5 


1865 


-0.8 


-0.8 


+1.2 


+1.3 


+3.7 


+0.4 


+1.7 


+0.5 


+2.9 


-0.9 


-1.9 


+ 1.8 


+ 9.1 


1866 


+0.1 


-0.7 


-0.1 


-0.5 


-2.3 


+0.0 +1.4 


+0.6 


+7.1 


+0.8 


-1.3 


-0.8 


+ 7.5 


3867 


-1.0 


+1.8 


+1.2 


-0.5 


+0.4 


-0.7 1-0.2 


-0.5 


-2.2 


+0.6 


-0.7 


+1.2 


- 0.6 


1868 


-0.3 


-2.0 


+1.7 


+0.4 


+1.9 


+0.9 


-1.0 


+1.5 


+4.6 


-0.9 


-0.8 


-0.8 


+ 5.0 


1869 


-0.5 


-0.3 


+0.4 


-0.3 


+1.0 


±0.0 


+0.4 


-1.1 


+1.0 


-0.4 


+0.8 


+0.1 


+ 1.1 


1870 


+2.8 


-0.1 


+0.4 


-0.7 


-1.7 


-0.2 


+0.3 


-0.2 


-1.6 


+0.5 


+1.0 


-0.7 


- 2.2 


1871 


-1.3 


-0.5 


-1.2 


-1.2 


-0.8 


-0.6 


-1.1 


+1.1 


-1.7 


-0.6 


-0.1 


-0.4 


- 8.4 


1872 


-2.5 


-1.3 


-2.3 


+1.5 


-0.7 


-1.2 


+2.1 


-0.2 


-1.4 


+0.1 


-1.8 


-0.5 


-8.2 


1873 


-0.9 


+0.4 


-0.7 


-0.3 


+0.2 


-0.4 


+1.6 


+0.5 


-0.7 


+2.1 


-1.7 


+2.0 


+ 3.1 


1874 


+0.8 


+0.9 


-0.3 


+2.0 


-2.3 


-1.1 


+1.0 


-0.9 


-0.3 


-1.9 


+1.1 


+0.5 


-0.5 


1875 


-1.7 


-1.4 


+0.2 


-1.5 


-0.4 


+1.1 


+4.8 


-0.2 


-0.9 


+0.2 


+1.5 


+0.6 


+ 2.3 


1876 


+2.7 


-0.7 


±0.0 


-0.5 


-1.0 


-0.4 


+2.9 


+0.2 


+2.6 


±0.0 


-0.4 


-1.6 


+ 3.8 


1877 


-0.5 


-2.5 


+1.7 


-0.5 


-1.3 


+1.7 


-0.1 


-1.5 


-0.8 


-0.5 


+0.7 


-0.6 


-4.4 


1878 


-0.4 


-1.5 


-0.8 


-0.8 


-1.0 


±0.0 1+0.1 


-0.1 


+1.2 


+0.3 


+0.4 


+0.6 


- 2.0 


1879 


-0.4 


-0.4 


+0.5 


-2.2 


-1.4 


+0.4 j+0.3 


+2.8 


-0.2 


-1.6 


+0.4 


+1.7 


- 0.1 


1880 


+0.9 


+1.0 


±0.0 


+2.3 


-0.4 


+0.9 |-1.2 


+1.3 


-0.4 


-0.1 


+0.2 


+0.2 


+ 4.7 


1881 


-0.5 


+0.2 


±0.0 


-0.8 


-1.4 


+0.5 '±0.0 


-1.7 


-0.5 


+2.3 


+0.8 


+2.0 


+ 0.9 


1882 


+2.5 


+2.1 


+1.0 


-0.3 


+4.1 


+1.6 1-1.1 


+ 1.7 


+0.3 


-0.6 


-1.2 


-1.1 


+ 9.2 


1S83 


-0.5 


+4.1 


-0.9 


+1.0 


+1.4 


+0.7 


-0.4 


-1.7 


-0.7 


+3.0 


+0.7 


+1.5 


+ 8. 



17 

Table 3. — Departure of monthly precipitation from normals, Ohio watershed above 
Cincinnati, Ohio, 1861 to 1910, inclusive — Continued. 



Years. 



1884. 
1885. 
1886. 
1887. 
1888. 
1S89. 
1890. 
1891. 
1892. 
1893. 
1894. 
1895. 
1896. 
1897. 
1898. 
1899. 
1900. 
1901. 
1902. 
1903. 
1904. 
1905. 
1906. 
1907. 
1908. 
1909. 
1910. 



1861-1870. 
1871-1880. 
1881-1S90. 
1891-1900. 
1901-1910. 



Jan. 



In. 
+0.4 
+1.9 
+0.3 
-0.7 
+1.3 
+0.4 
+1.9 
±0.0 
-1.0 
-0.5 
-0.9 
+1.6 
-1.8 
-1.3 
+3.3 
+0.7 
-0.9 
-1.8 
-1.0 
-1.1 

0.8 
-1.4 
-0.9 
+4.0 
-1.8 
—2 2 
+U 



+0.3 
-0.3 
+0.7 
-0.1 
-0.6 



1861-1885 +0.1 

1886-1910 -0.1 



Feb. Mar. 



In. 

+2.9 
-0.9 
-1.4 
+4.1 
-1.4 
-1.6 
+2.7 
+1.7 
-0.1 
+2.2 
+0.5 
-2.5 
-0.6 
+2.1 
-1.] 
-0.5 
±0.0 
-2.1 
-2.1 
+2.5 
1.1 
-1.5 
1.6 
2.0 
+1.4 
+2.7 
+1.1 



In. 
+0.3 
-2.8 
-0.5 
-1.7 
+0.5 
-2.5 
+2.6 
+ 1.3 
-0.8 
-1.8 
-1.6 
-1.4 
+0.3 
4-2.2 
+3^4 
+1.9 
-1.6 
-1.1 
-0.7 
+0.4 
+2.1 
-0.3 
+1.5 
+2.0 
+2.2 
-0.8 
-3.5 



Apr. | May. June. 



In. In. 

-0.7 +0.4 

+0.4 +0.1 

-0.2 +1.4 

+1.9 +0.0 

-1.1 +0.1 

-1.2 -0.1 

+0.1 +1.3 



-1.0 
+1.1 
+3.3 
-0.2 
-0.8 
-1.3 
+0.8 



1.4 
+1.6 
+0.8 
±0.0 
-1.4 
-0.5 
+0.3 



0.5 '+0.2 
-0.6 -0.3 
+1.1 -0.4 
+0.2 +0.2 

0.3 '+0.2 



0.1 
+0.1 



-0.1 
-0.1 



0.9 +0.9 
1.4 1+0.6 
-1.1 
+0.1 
-0.4 
-1.0 
-0.5 



-1.4 
+1.1 
-1.0 
+0.2 
-0.3 



±0.0 +2.4 
-1.6 !-1.3 
-0.4 -0.3 
+0.9 |+1.1 
+1.4 j+0.6 
-0.3 1+0.7 



+0.2 +0.2 
-0.1 -0.9 
-0.1 I+0.7 
-0.2 ±0.0 
±0.0 +0.1 



±0.0 1-0.1 
-0.1 1+0.2 



In. 
-1.1 
-0.3 
+0.3 
-0.4 
-1.4 
±0.0 
+0.6 
+1.0 
+0.9 
+0.1 
-0.9 
-1.1 
+0.4 
-0.8 
iO.O 
-0.5 
-1.2 
+0.8 
+2,9 
±0.0 
-0.7 
+0.5 
+0.2 
+0.7 
-1.6 
+ 2.1 
-0.7 



July. 



In. 
-1.1 
-1.8 
-0.7 
-0.6 
+1.1 
+1.6 
-1.8 
+0.7 
+0.1 
-1.1 
-2.2 
-1.9 
+5.0 
+1.4 
+0.1 

0.5 
-0.3 
-1.7 
-1.0 
-0.9 
-1.5 
-0.7 
+1.1 
+2.0 
-0.5 
±0.0 
-0.4 



-0.3 1-0.3 
±0.0 +1.0 
+0.1 -0.5 
-0.2 i+0.1 
+0.4 -0.4 



±0.0 
+0.1 



+0.1 
-0.1 



Aug. 



In. 
-1.8 
+2.5 
+0.1 
-0.9 
+4.8 
-2.0 
+1.8 
-0.2 
-0.3 
-1.3 
-0.5 
-0.4 
+0.4 
-0.9 
+0.9 
-0.7 
+0.6 
+0.2 
-1.6 
-1.2 
-1.1 
+1.3 
+1.2 
-0.4 
-0.5 
-0.5 
-1.2 



+0.3 

+0.3 

+0.3 

0.2 

0.4 



+0.2 
0.1 



Sept. 



Oct. 



In. 

+0.9 
-0.4 
+0.6 
-0.5 



In. 
+1.0 
-1.2 
-1.3 
-1.9 



-0.9 1+1.7 
+1.0 -1.3 
+2.6 '+1.5 
-1.2 -0.8 



±0.0 
-0.8 
-0.1 
-1.9 
+1.8 
-2.0 
-0.3 
-0.3 
-1.7 
-0.7 
+0.4 



-1.9 
+2.1 
-0.9 
-1.3 
-0.6 
-2.0 
+1.6 
-0.4 
-0.8 
-1.8 
±0.0 



-1.8 ,-0.2 
-1.6 -1.3 



+0.2 
+0.3 
-0.4 
-2.6 
-1.0 
+1.6 



+2.3 
-0.3 
-0.2 
-1.3 
-0.1 
+1.3 



+1.1 

-0.3 

+0.2 

0.6 

0.6 



+0.4 
0.4 



+0.2 
-0.2 
+0.5 
-0.5 
-0.2 



+0.2 
-0.3 



Nov. 



In. 
-1.4 
-0.2 
+1.-8 
-0.2 
+1.7 
+1.9 
-0.2 
+2.0 
-0.2 
-0.5 



Dec. 



In. 
+1.1 
-1.2 
-0.5 
-0.3 
-1.5 
-0.5 
+0.5 
-0.6 
-1.0 
-0.4 



0.9 +0.4 
+1.0 +0.6 



+0.3 
+3.5 
+0.3 
+0.9 
+2.2 
-1.4 
-0.1 
-0.7 
-2.5 
-0.1 
±0.1 
-0.7 
-1.7 
-1.2 
-1.4 



±0.0 
+0.1 
+0.4 
+0.7 
1.0 



±0.0 
+0.1 



1.3 
+0.4 
-0.3 
±0.0 
-1.3 
+ 1.0 
+1.8 
-1.2 
+0.3 
-0.2 
+0.9 
-0.1 
-1.0 
-0.4 
-0.3 



±0.0 
+0.2 
±0.0 
-0.4 
+0.1 



+0.2 
-0.2 



An- 
nual. 



In. 

- 1.1 
-1.5 
-0.1 
-1.2 
+ 4.9 

- 3.3 
+ 13.6 
+ 1.5 

- 1.6 
+ 2.1 

- 7.3 

- 9.6 
+ 2.1 
+ 3.7 
+ 7.9 

- 2.0 
-7.4 
-7.5 

- 2.8 

- 5.0 
-9.0 
+ 2.5 

- 0.4 
+ 4.2 
-5.4 
+ 0.6 
-1.7 



+ 1.5 

- 1.3 
+ 3.0 

- 1.0 
-2.7 



+ 0.8 
- 0.8 



Table No. 4. 



The number of days that the river stages were between each 5 
or 10 feet for each month and the year for each 10-year period is 
shown in Table 5, together with the totals for the 50 years and the 
means for each 10-year period. The yearly averages can be obtained 
by dividing the 10-year averages by 10. 

If it is true that the cutting away of the forests has increased 
flood conditions and intensified low-water periods, it seems to the 
writer that there would be a regular increase in the low-water days 
in the months of July, August, and September, and that this increase 
would appear in the 10-year periods in the table. On the contrary, 
there were only 64 days from 1901 to 1910, inclusive, when the river 
was between 5 and 10 feet during the month of July, as compared 
with 179 days from 1861 to 1870, inclusive. In October there were 
only 96 days in the 10 years from 1901 to 1910, inclusive, when the 
river was below 5 feet, as compared with 177 days in the 10 years 
from 1871 to 1880, inclusive. The high-water days should show a 
regular increase also during the months from January to April, 
inclusive, but such is not the case. 
21464—12 3 



18 

Table 4. — Total number of days in each month with river readings between values 
indicated at Cincinnati, 10-year 'periods, 1861 to 1910, inclusive. 

TO 4.9 FEET. 



Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June.j July. 
1 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Total. 


1861-1870 


Days. 







Days. 







Days. 







Days. 







Days. 

6 





Days. 
8 


5 



Days. 
18 
18 
11 
19 



Days. 
41 
29 
42 
53 
17 


Days. 

88 

100 

124 

96 

73 


Days. 

93 
177 
113 
193 

96 


Days. 
30 
66 
65 

68 
84 


Days. 

8 
1 
8 
1 
36 


Days. 
286 


1871-1880 


391 


1881-1890 


363 


1891-1900 


435 


1901-1910 


306 











5 TO 9.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



6 


10 








9 


SI 


179 


171 


97 


114 


121 


48 


34 


14 


6 


4 


46 


160 


145 


167 


159 


107 


79 


63 


9 


7 


4 


1 


10 


50 


132 


147 


68 


108 


48 


41 


29 











38 


72 


154 


150 


181 


62 


134 


79 


14 


22 


' 





23 


26 


64 


164 


141 


142 


124 


80 



836 
984 
625 



10 TO 19.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



124 


86 


34 


29 


147 


167 


94 


98 


82 


72 


95 


140 


102 


93 


72 


116 


162 


135 


127 


100 


22 


22 


133 


147 


89 


49 


79 


95 


172 


161 


135 


112 


89 


58 


100 


171 


128 


81 


48 


89 


149 


185 


115 


84 


23 


46 


80 


161 


137 


104 


34 


71 


147 


175 


204 


123 


86 


71 


71 


103 



1,168 
1,231 
1,310 
1,189 
1,326 



20 TO 29.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



90 


99 


116 


152 


99 


44 


19 





21 


22 


53 


71 


96 


106 


122 


104 


74 


5 


6 


3 


12 


4 


17 


54 


119 


67 


105 


101 


78 


66 


30 


6 


14 


23 


63 


65 


74 


82 


111 


128 


90 


34 


16 


11 





9 


15 


64 


86 


SO 


86 


133 


92 


76 


42 


6 





1 


17 


54 



786 
603 
737 
634 
673 



30 TO 39.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



64 


59 


99 


70 


45 











8 


7 


1 


36 


50 


43 


94 


■61 


21 





14 


2 


7 





5 


32 


56 


45 


69 


69 


39 


23 


2 


3 


5 


8 


24 


17 


42 


67 


104 


55 


22 


4 


4 


10 








3 


6 


40 


45 


69 


58 


26 


18 














4 


29 



389 
329 
360 
,317 
289 



40 TO 49.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



14 


21 


44 


43 


8 











4 


2 





7 


23 


23 


16 


15 


7 








4 











13 


37 


55 


38 


22 


11 




















8 


32 


30 


31 


23 


9 





2 


2 











1 


22 


25 


80 


25 


21 


5 

















8 



143 
101 
171 
130 

186 



50 TO 59.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



12 


7 


17 


6 


2 























6 


4 

















5 

















39 


15 


12 


























5 


20 


14 


5 


2 























5 


6 


30 


13 


1 
























60 TO 69.9 FEET. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 














































































18 



































2 


2 





























6 





4 























0. 






19 



Table 4. — Total number of days in each month ivith river readings between values 
indicated at Cincinnati, 10-year periods, 1861 to 1910, inclusive — Continued. 

70 TO 79.9 FEET. 



Years. 


Jan. i Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct, 


Nov. 


Dec. 


Total. 


1861-1870 


Days. 







Days.iDays. 

j 
2 


Days. 





• 





Days. 







Days. 







Days. 




Days. 




Days. 







Days. 



Days. 



Days. 





Days. 



1871-1880 











1881-1890 


1 












2 


1891-1900 

















1901-1910 


















Totals for 50 years and means for each 10-year period. 

TO 4.9 FEET. 

























13 

3 


66 
13 


182 
36 


481 
96 


672 
134 


313 
63 


54 
11 


1 


781 




356 














5 TO 9.9 


FEET. 














92 
18 


53 
11 


17 
3 


5 

1 


126 
25 


389 

78 


674 
135 


799 
160 


646 
129 


533 
107 


506 
101 


309 
62 


4,149 
830 
















10 TO 19.9 


FEET. 














580 
116 


413 

83 


267 
53 


400 
80 


777 
155 


S24 
165 


675 
135 


517 
103 


302 
60 


269 
54 


479 
96 


722 
144 


6,225 




1,244 














20 TO 29.S 


FEET. 












Sums 

Means 


464 
93 


434 

87 


540 
108 


619 ! 433 
124 87 


235 
47 


113 

23 


26 
5 


47 
9 


59 
12 


165 
33 


308 
62 


3,433 

687 










30 TO 39. 1 


FEET. 














252 
50 


259 
52 


435 

85 


313 
63 


153 
31 


45 
9 


20 
4 


15 
3 


20 
4 


15 
3 


37 

7 


120 1,685 




24 337 














40 TO 49.£ 


FEET. 












Sums 

Means 


128 
26 


154 
31 


209 
42 


128 1 56 
26 ' 11 


5 

1 


2 



6 
1 


4 
1 


2 







37 

7 


731 

146 










50 TO 59.£ 


FEET. 














28 
6 


76 
15 


76 
15 


36 

7 


5 
1 










5 
1 


















226 




45 














60 TO 69.S 


FEET. 














6 

1 


20 
4 


6 
1 







































3? 




6 














70 TO 79.{ 


FEET. 


















2 

































2 


Means 




















20 



Table No. 5. 

This table shows the number of days the river at Cincinnati was 
between each 5 or 10 feet for each month and the year for the two 
25-year periods, 1861 to 1885 and 1886 to 1.910, all inclusive. 

It will be seen that there was very little difference between the total 
number of flood days of the two periods during the months of January 
and February, while during the months of March and April the 
greater number occurred in the second period. It will also be seen 
that the low-water days were in excess in the first period during the 
months from June to September, inclusive, while during the second 
period the low-water days were in excess in November and December. 

Flood conditions are not the products of precipitation extending 
over any considerable period of time, but are, as a rule, the results of 
abnormal precipitation within a comparatively short time, and there 
is therefore no direct relation between the average annual precipita- 
tion and the number of flood days and the intensity of flood con- 
ditions. On the other hand, low-water periods are usually the results 
of prolonged periods of deficient precipitation, and the relation between 
the two is therefore quite clearly marked. 

Table 5. — Total number of days in each month with river readings between values 
indicated at Cincinnati, 25-year periods, 1861 to 1910, inclusive. 











0.0 TO 4.9 


FEET. 














Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov.. 


Dec. 


Total. 


1861-1885 


Days. 




Days. 




Days. 




Days. 




Days. 




Days. 

8 
5 


Days. 
39 
27 


Days. 
93 
89 


Days. 
271 
210 


Days. 
335 
337 


Days. 
120 
193 


Days. 
13 
41 


Days. 

879 


1886-1910 


902 






5 TO 9.9 FEET. 


1861-1885 

1886-1910 


45 
47 


28 
25 


10 

7 


5 



57 
69 


261 
128 


397 
277 


408 
391 


275 
371 


280 
253 


242 
264 


125 

184 


2,133 
2,016 






10 TO 19.9 FEET. 


1861-1885 


275 
305 


203 
210 


128 
139 


181 
219 


403 385 
374 439 


289 
386 


259 
258 


152 
150 


125 
144 


301 
178 


389 
333 


3,090 


1886-1910 


3,135 














20 TO 29.9 FEET. 












1861-1885 


234 
230 


228 
206 


300 
240 


317 
302 


215 

218 


81 
144 


36 

77 


4 
22 


33 
14 


26 
33 


81 
84 


137 
171 


1,692 


1886-1910 


1,741 






30 TO 39.9 FEET. 


1861-1885 


138 
114 


120 
139 


239 
196 


171 
141 


79 

74 


16 ' 14 
29 6 


2 
13 


15 
5 


7 
8 


6 
31 


83 
37 


890 


1886-1910 


793 






40 TO 49.9 FEET. 


1861-1885 


65 
63 


70 
84 


81 
128 


70 
58 


19 
37 



5 



2 


4 
2 


4 



2 







28 
9 


343 


1886-1910 


388 







21 



Table 5. — Total number of days in each month with river readings between values 
indicated at Cincinnati, 25-year periods, 1861 to 1910, inclusive — Continued. 



50 TO 59.9 FEET. 



Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Total. 


1861-1885 


Days. 
18 
10 


Bays. 
37 
39 


Days. 
17 
59 


Days. 

6 

30 


Days. 
2 
3 


Days. 




Days. 




Days. 
5 



Days. 




Days. 




Days. 





Days. 




Days. 
85 


1S86-1910 


141 






60 TO 69.9 FEET. 


1861-1885 



6 


18 
2 



6 












! 



o 1 






18 


1886-1910 


14 


70 TO 79.9 FEET. 


1861-1885 






2 
















n 


























2 


1886-1910 














Table No. 6. 

In this table is given the average precipitation and the average 
number of days the river at Cincinnati was above 50 feet, below 
5 feet, and below 10 feet for each month and the year for each 10-year 
and each 25-year period. 

Table 6. — Average precipitation in the Ohio watershed above Cincinnati, and days with 
the river above 50 feet, below 5 feet, and below 10 feet at Cincinnati, 1861-1910, 
inclusive. 

1861 TO 1870, INCLUSIVE. 









Mar. 
Apr. 


03 


o3 

a 
1-3 


>-> 


hi 

< 


ft 

OJ 
CO 




O 


> 





Total. 


Rainfall (inches) 


3.7 


2.7 


4.0; 3.4 


3.8 


3.6 


3.8 


3.6 


4.1 


2.6 


2.8 


3.0 


41.1 




12 

6 


7 

10 


17l 6 




2 


9 



8 
89 




18 

197 




41 

212 



88 
185 




93 

207 


(i 
30 
151 




8 

56 


44 


Days with river below 5 feet 


286 
1,122 




1 




1871 T( 


D 1880, INCLUSIVE. 












Rainfall (inches) 


3.1 2.6 


3.5 3.1 


2.7 


1 
3.9 5.1 


3.6 


2.7 


2.2 


2.9 3.2 


38.6 




6 4 








46 


ol 

18 
160 163 


5 
29 
196 



100 
259 




177 
284 



66 ! 1 
145 64 


15 










391 




34 14 6 4 


1,375 




1881 T( 


3 1890, INCLUSIVE. 












Rainfall (inches) 


4.1 


4.3 


3.4 


3.1 


4.3 


4.0 3.0 


3.6 


3.2 


2.9 


3.2 


3.0 


42.7 






9 


59 


7 


15 

4 


12 

1 





10 


(l (l 
11 
50! 143 




42 
189 



124 
192 



113 
221 


0! 

65 S 
113 49 


86 




363 




988 






1891 T( 


3 1900, INCLUSIVE. 












Rainfall (inches) 


3.3 3.4 


4.0 


3.0 


3.6 


3.7 


4.2 


3.1 


2.4 


1.9 


3.5 2.6 


38.7 




5 22 16 


5 2 

38 



5 
77 



19 
173 




53 

203 



96 

277 



193 
255 




68 1 

202 78 


50 





29 










435 




1,332 

















22 

Table 6. — Average precipitation in the Ohio watershed above Cincinnati, and days with 
the river above 50 feet, below 5 feet, and below 10 feet at Cincinnati, 1861-1910, inclu- 
sive — Continued . 

1901 TO 1910, INCLUSIVE. 





a 

C8 




a 


ft 

< 


a 


a 

s 

Ha 






ft 


o 
O 


> 

o 


P 


Total. 


Rainfall (inches) 


2.8 


2.9 


4.0 


3.2 


3.7 


4.3 


3.7 


2.9 


2.4 


2.2 


1.8 


3.1 


37.0 




11 


14 


6 34 


22 7 


13 




1 



23 






26 





64 



17 
181 




73 

214 



96 

238 




84 
208 



36 
116 


65 




306 




1,113 











1861 TO 1885, INCLUSIVE. 



Rainfall (inches) 

Days with river above 50 feet. 
Days with river below 5 feet. . 
Days with river below 10 feet. 



3.5 


3.1 


3.7 


3.2 


3.5 


3.9 


4.2 


3.5 


3.3 


2.6 


2.8 


3.2 


18 


57 


17 


6 


2 








5 





























8 


39 


93 


271 


335 


120 


13 


45 


28 


10 


5 


57 


269 


436 


501 


546 


615 


362 


138 



40.5 



105 

879 
3,012 



1886 TO 1910, INCLUSIVE. 



Rainfall (inches) 


3.3 

16 


47 


3.3 

41 

?5 


3.9 

65 

7 


3.1 

30 




3.8 

3 


69 


4.0 



5 

133 


4.0 


27 

306 


3.2 



89 
480 


2.6 


210 

581 


2.1 


337 
590 


2.9 


193 
457 


2.8 


41 

215 


38.8 
155 




902 




2,910 











Table No. 7. 

This table is supplementary to Table 6, and gives the departures 
from the normals for the same data as are shown in Table 6. In 
these tables we begin to observe the effect of precipitation upon 
river stages. 

Table 7. — Departures of precipitation and river-stage days from normals at Cincinnati 
for days above 50 feet, below 5 feet, and below 10 feet, 1861-1910. 





1861 TO 1870, INCLUSIVE 


















3 




3 

a 


ft 
< 


a 


P 
3 


1-3 


3 


ft 

02 


o 
O 


o 


6 

a* 

P 


3 
C 

a 
< 




+0.3 


-0.5 


+0.2 


+0.2 


+0.2 


-0.3 


-0.3 


+0. 3J+1. 1 


+0.2 








+ 1 5 








T 5 


- 13 


+ 1 


- 2 


+ 1 






- 1 

+ 5 










- 8 






+ 5 
+ 9 


+ 5 
+ 48 


- 8 


- 39 

- 34 


- 33 

- 13 


- 3 

- 17 


- 70 




-12- 1 


- 3 


- 1 


- 17 


+ 16-45 


- 65 

















1871 TO 1880, INCLUSIVE. 
















Precipitation (inches) 


-0.3 


-0.6 


-0.3 


-0.1 


-0.9 





+ 1.0 


+0.3 


-0.3 


-0.2 


+0.1 


+0.2 


-1.3 




1 


- 16 


-16 


- 8 


- 1 








- 7 











- 37 






- 3 

+ 80 


+ 5 
+ 14 


+ 4 
+ 34 


+ 43 
+ 43 


+ 3 
- 19 


- 10 

- 9 


+ 35 




+ 16 


+ 3+ 3 


+ 3 


+ 21 


+ 188 













1881 TO 1890, INCLUSIVE. 





+0.7 


+1.1 
+ 39 


-0.4 


-0.1 


+0.7 


+0.1 


-0.5 


+0.3 


+0.2 


+0.5 


+0.4 





+3 








- 7 


- 1 


+ 4 


- 1 






- 1 

+ 6 

- 7 










+ 34 




- 3 
- 30 


- 4 

- 5 


+ 28 
- 33 


- 21 

- 20 


+ 2 
- 54 


- 3 
+ 24 


+ 7 




- 9 


- 4 


+ 1 





- 15 


-198 







23 



Table 7. — Departures of precipitation and river-stage days from normals at Cincinnati 
for days above 50 feet, below 5 feet, and below 10 feet, 1861-1910, inclusive — Continued. 



1891 TO 1900, INCLUSIVE. 





a 

t!3 




C 

a 

£ 


p. 
< 


03 

<5 


June. 
My. 


< 


ft 
as 


o 
O 


> 
o 


Dee. 
Annual. 




-0.1 


+0.2 


+0.2 


-0.2 





-0.2 


+0.1 


-0.2 


-0.6 


-0.5 


+0.7 


-0.4-1.0 










- 2 


+ 2 





- 3 


+ 1 






- 1 

+ 17 

+ 7 










_ 9 




+ 2 
- 3 


+ 6 
+ 24 



+ 52 


+ 59 

+ 14 


+ 5 
+ 38 


- 10 

+ 5 


+ 79 




+ 11 


- 11 


- 3 


- 1 


+ 13 


+ 145 







1901 TO 1910, INCLUSIVE. 



Precipitation (inches) . 



Days above 50 feet . 
Days below 5 feet . . 
Days below 10 feet . 



-0.6 


-0.3 


+0.2 
+ 18 




+ 5 


+0.1 


+0.4 


-0.4 


-0.4 

^~\ 

- 19 

- 15 


-0.6 


-0.2 


-1.0 


+0.1 


+ 4 


- 14 















- 3 

- 54 


- 13 

- 85 


- 23 

- 11 


- 38 
- 3 


+ 21 
+ 44 


+ 25 
+ 43 


- 4 


+ 11 




+ 4 


- 1 


- 2 



-2.7 

+ 13 
50 

74 



1861 TO 1885, INCLUSIVE. 



Precipitation (inches) . 



Days above 50 feet . 
Days below 5 feet . . 
Days below 10 feet. 



+0.1 


-0.1 


-0.1 





-0.1 


+ ""2 
+ 68 


+ 0.1 

+ "6 
+ 67 


+0.2 


+ 0.3 


+ 0.2 





+0.2 


+ 1 


+ 8 


-24 


- 12 





+ 3 
+ 2 
+ 11 


+ '31 
- 18 


+ 13 


— 36 


— 14 


- 1 


+ 2 


+ 2 


+ 3 


- 6 


- 48 


- 44 



+0.8 

25 
11 
49 



TO 1910, INCLUSIVE. 





-0.1 


+0.1 


+0.1 


-0.1 


+0.2 


+0.1 


-o.i 
-"e> 

- 68 


-0.1 

- 2 

- 2 

- 10 


-0.'4 


-0.3 


+0.1 


-0.2 


-0.8 








- 1 


- 8 


+ 24 


+ 12 


+ 1 


-68 


-"36 
+ 17 


+"i 

- 12 


+ "37 
+ 47 


+ 14 
+ 43 


+ 25 


Days below 5 feet 


+ 11 




+ 1 


- 1 


- 1 


_ 2 


+ 6 


— 48 







Table No. 8. 

In this table is shown the comparison between the departures of 
the precipitation from the normals for each month of each 10 years, 
and the number of days the river stages were above or below the nor- 
mal number of days for the different 5 or 10 foot heights for the same 
10-year periods. 



Table 8. 



-Departures of precipitation and river-stage days from normals, Ohio Watershed 
above Cincinnati, 1861 to 1910, inclusive. 



PRECIPITATION. 



1861-1870. 
1871-1880. 
1881-1890. 
1891-1900. 
1901-1910. 



Jan. 


Feb. 


Mar. 


Apr. 


Maj'. 


June. 


July. 


Aug. 


Sept. 


Oct. 


+0.3 


-0.5 


+0.2 


+ 0.2 


+0.2 


-0.3 


-0.3 


+ 0.3 


+ 1.1 


+0.2 


-0.3 


-0.6 


-0.3 


-0.1 


-0.9 





+ 1.0 


+0.3 


-0.3 


-0.2 


+0.7 


+1.1 


-0.4 


-0.1 


+0.7 


+0.1 


-0.5 


+0.3 


+ 0.2 


i 0.5 


-0.1 


+0.2 


+0.2 


-0.2 





-0.2 


+0.1 


-0. 2 


-0.6 


-0.5 


-0.6 


-0.3 


+ 0.2 





+0.1 


+0.4 


-0.4 


-0.4 


-0.6 


-0.2 



An- 
nual. 









+ 0.1 


+0.2 


+ 0.4 





+0.7 


-0.4 


-1.0 


+0.1 



+ 1.5 
-1.3 
+3. 
-1.0 
-2.7 





DAYS WITH RIVEP. 


TO 


4.9 FEET, 


[NCLUSIVE. 








1861-1870 












+ 5 

- 3 

- 3 
+ 2 

- 3 


+ 5 
+ 5 
- 4 
+ 6 
-13 


+ 5 

+ 6 
+ 17 
-19 


- 8 
+ 4 
+28 

-23 


-39 
+43 
-21 
+59 
-38 


-33 
+ 3 
+ 2 
+ 5 
+21 


- 3 
-10 

- 3 
-10 
+ 25 


-70 


1871-1880 












+ 35 


1881-1890... 












+ 7 


1891-1900 












+ 79 


1901-1910 












-50 

















24 



Table 



-Departures of -precipitation and river -stage days from normals, Ohio watershed 
above Cincinnati, 1861 to 1910, inclusive — Continued. 



DAYS WITH RIVER 5 TO 9.9 FEET, INCLUSIVE. 





Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. Sept. 


Oct. 


Nov. 


Dec. 


An- 
nual. 


1861-1870 


-12 
+ 16 

- 9 
+ 11 

- 4 


- 1 

+ 3 

- 4 
-11 
+11 


- 3 

+ 3 

+ 1 

- 3 
+ 4 


- 1 
+ 3 



- 1 

- 1 


-16 
+21 
-15 
+ 13 
- 2 


+ 3 

+82 
-28 
- 6 
-52 


+44 
+10 
- 1 
+ 19 
-71 


+11 | -32 
+ 6 1 +30 
-13 1 -61 
-10 +52 

+ 4+12 


+ 7 

+ 1 
-45 
+25 


+20 
-22 
-53 
+33 

+ 13 


-14 
+ 1 
-21 
+15 
+ 18 


+ 6 


1871-1880 


+154 


1881-1890 


—203 


1891-1900 


+ 69 


1901-1910 


- 23 



DAYS WITH RIVER 10 TO 19.9 FEET, INCLUSIVE. 



1861-1870. 
1871-1880. 
1881-1890. 
1891-1900. 
1901-1910. 



+ 8 


+ 2 


-19 


-51 


- 8 


+ 2 


-41 


- 5 


+ 22 


+18 


- 1 


- 4 


-14 


+ 10 


+ 19 


+36 


+ 7 


-30 


- 8 


- 3 


-38 


-32 


+37 


+ 3 


-27 


-34 


+26 


+15 


+ 17 


- 4 


- 2 


+ 9 


+29 


+ 4 


+ 4 


+27 


+ 12 


- 2 


- 7 


+ 9 


- 6 


+20 


-20 


-19 


-37 


- 8 


-16 


+17 


+21 


+21 


-19 


- 9 


- 8 


+ 10 


+ 69 


+20 


+26 


+ 17 


-25 


-41 



-76 
-13 
+64 
-55 

+82 



DAYS WITH RIVER 20 TO 29.9 FEET, INCLUSIVE. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



- 3 


+12 


+ 8 


+28 


+ 12 


- 3 


- 4 


— 5 


+ 12 


+ 10 


+20 


+ 9 


+ 3 


+ 19 


+ 14 


-20 


-13 


-42 


-17 


- 2 


+ 3 


- 8 


-16 


- 8 


+26 


-20 


- 3 


-23 


- 9 


+ 19 


+ 7 


+ 1 


+ 5 


+ 11 


+30 


+ 3 


-19 


- 5 


+ 3 


+ 4 


+ 3 


-13 


— 7 


+ 6 


- 9 


- 2 


-18 


+ 2 


- 7 


- 7 


-22 


+ 9 


+ 5 


+29 


+ 19 


+ 1 


- 9 


-11 


-16 


- 8 



+99 
-84 
+50 
-53 
-14 



DAYS WITH RIVER 30 TO 39.9 FEET, INCLUSIVE. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



+ M 


+ 7 


+12 


+ 7 


+ 14 


- 9 


- 4 


- 3 


+ 4 


+ 4 


- 6 


+12 





- 9 


+ 7 


- 2 


-10 


- 9 


+ 10 


- 1 


+ 3 


- 3 


- 2 


+ 8 


+ 6 


- 7 


-18 


+ 6 


+ 8 


+ 14 


- 2 





+ 1 


+ 5 


+17 


- 7 


- 8 


+ 15 


+17 


- 8 


- 9 


- 5 





+ 7 


- 4 


- 3 


- 4 


-18 


-10 


- 7 


-18 


- 5 


- 5 


+ 9 


- 4 


- 3 


- 4 


- 3 


- 3 


+ 5 



+52 
- 8 
+23 
-20 
-48 



DAYS WITH RIVER 40 TO 49.9 FEET, INCLUSIVE. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



-12 

- 3 
+ 9 
+ 6 

- 4 


-10 

- 8 
+24 

- 1 

- 6 


+ 2 
-26 

- 4 
-11 
+38 


+ 17 
-11 

- 4 

- 3 

- 1 


- 3 

- 4 


- 2 
+ 10 


- 1 

- 1 

- 1 

- 1 

+ 4 





+ 2 



- 1 
+ 3 

- 1 
+ 1 

- 1 


+ 3 

- 1 

- 1 

- 1 

- 1 


+ 2 









+ 6 
+ 1 
- 6 

+ 1 



- 3 
-45 

+25 
-16 
+ 40 



DAYS WITH RIVER 50 TO 59.9 FEET, INCLUSIVE. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



+ 6 


- 6 

- 1 

- 1 


-8 
-11 
+24 
+ 5 
- 9 


+ 2 

-15 



- 1 

+ 15 


- 1 

- 7 
+ 5 

- 2 
+ 6 


+ 1 

- 1 

- 1 
+ 1 

























































































- 1 

-30 

+21 
+ 1 
+10 



DAYS WITH RIVER 60 TO 69.9 FEET, INCLUSIVE. 



1861-1870 
1871-1880 
1881-1890 
1891-1900 
1901-1910 



-V 1 

- 1 

- 1 

- 1 

+ 5 


- 4 

- 4 
+14 

- 2 

- 4 


- 1 

- 1 

- 1 

+ 1 
+ 3 















































































































+ 12 
- 2 

+ 4 



DAYS WITH RIVER 70 TO 79.9 FEET, INCLUSIVE. 


1861-1870 





























1871-1880 





























1881-1890 


























+ 2 


1891-1900 





























1901-1910 



























































25 

Table No. 9. 

This table shows the number of days the Ohio River at Cincinnati 
was above the flood stage of 50 feet for each month during the entire 
50 years, together with the totals for each year and for each month. 



Table 9.- 



■Total number of days with river above 50 feet at Cincinnati, Ohio, 1861 to 1910 , 
inclusive. 



Years. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June. 



July. 



Aug. 



Sept. 



Oct. 



Nov, 



Dec. 



An- 
nual. 



1861 

1862 

1863 

1864 

1865 

1866 

1867 

1868 

1869 

1870 

1871 

1872 

1873 

1874 

1875 

1876 

1877 

1878 

1879 

1880 

1881 

1882 

1883 

1884 

1885 

1886 

1887 

1888 

1889 

1890 

1891 

1892 

1893 

1894 

1895 

1896 

1897 

1898 

1899 

1900 

1901.. 

1902 

1903 

1904 

1905 

1906 

1907 

1908 

1909 

1910 

Sums 



Days. 






7 












4 
2 
9 
16 
19 


10 


3 



Days. 




5 

12 



















3 


12 






2 
7 
7 


4 
8 




11 

6 
2 
3 



Days. 




2 



























2 








1 













Days. 





















































Days 





















































Days. 














5 






































Days. 





















































Days. 





















































Days. 






























































12 


7 

19 


6 




5 

1 

5 



4 
2 
9 

16 

19 


12 

13 



15 
8 


10 



8 

15 
9 




26 

Table No. 10. 

The table shows the number of clays the Ohio River at Cincinnati 
was above the 40-foot stage for each month during the entire 50 
years, together with the totals for each year and for each month. 

Table 10. — Total number of days with river above 40 feet at Cincinnati, Ohio, 1861 to 1910, 

inclusive. 



Years. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


An- 
nual. 


18G1 


Days. 
2 

10 
1 




3 


10 



6 


11 
9 


3 


23 


5 

3 


6 
6 
2 


5 



16 
8 


2 

4 



19 


8 


Days. 


10 
1 

2 


15 





3 
5 


10 


2 
7 
9 

20 

18 

25 

1 

28 



13 

26 


14 




12 




2 

14 




9 
5 
1 


Days. 

6 
3 

19 

19 
10 
2 
2 




5 
1 
3 


7 

6 

15 

1 
7 


24 
10 





14 
10 
13 


15 
19 
14 
11 

:l 
1 

12 


Days. 
7 

15 


6 


2 
6 

13 

5 

6 

1 



3 
3 

9 



16 
5 


1 
6 
6 
1 


6 

5 
4 


10 
3 
5 
5 

6 

9 




Days. 




8 


2 


1 


4 





2 

4 







7 


11 





o 



3 



6 


6 
7 



Days. 








































2 





3 





Days. 



































2 




.0 











Days. 














9 




















2 






q 











Days. 





2 

2 












































Days. 
2 



















































Days. 




















































Days. 



5 
2 







4 

4 


3 
2 

2 

6 
















1 

7 



1 








Days. 

11 


1862 


41 


1863 .. 


5 


1864 


5 


1865 


37 


1866 


2 


1867 


34 


1868 


19 


1869 


8 


1870 


25 


1871 


1 


1872 


5 


1873 


7 


1874 


21 


1875 


18 


1876 


23 


1877 


12 


1878 .. 


3 


1879 


4 


1880 


22 


1881 


14 


1882 


53 


1883 


33 


1884 


40 


1885 .. 


5 


1886 


18 


1887 


43 


1888 





1889 





1S90 


51 


1891 


48 


1892 


8 


1893 . . . 


26 


1894 





1895 


5 


1896 


10 


1897 

1898 


26 
31 


1899 

1900 


25 
1 


1901 


15 


1902 


29 


1903 


38 


1904 . . . 


23 


1905 


18 


1906 


7 


1907 

1908 


37 
43 


1909 


20 


1910 


21 








162 


252 


291 


164 


61 


5 


2 


11 


4 


2 





37 


991 







27 

Table No. 11. 

This table shows the number of days the Ohio River at Cincinnati 
was below the 10-foot stage for each month during the entire 50 years, 
together with the totals for each year and for each month. 

Table 11. — Total number of days with river below 10 feet at Cincinnati, Ohio, 1861-1910, 

inclusive. 



Years. 



Jan. 



Feb. 



Mar. 



Apr. 



May. 



June, 



July. 



Aug. 



Sept. 



Oct. 



Nov. 



Dec. 



Total. 



1861. 
1862. 
186c. 
1864. 
1865. 
186( . 
18..7 . 
1868 . 
1869. 
1870. 
1871. 
1872. 
187? . 
1874. 
1876. 
187( . 
1877. 
1878. 
1879. 
1880. 
1883. 
1882. 
188? . 



188f. 
1887. 
188?. 
188P . 
1890. 
189' . 
1892. 
189? . 
1894. 
1895. 
189'" . 
1897. 
ISW. 
189?. 
190". 
190" . 
1902 . 

mr. 

1904. 
1905. 
1906 . 
1907. 
1908 . 
1909. 
1910. 



Days. 











4 













1 





























Days, 



4 


5 




3 
8 

7 
6 



10 
12 
2 





3 
5 


* 20 


2 


10 



6 

4 
12 


7 







Dai/tt. 

12 



30 

11 



30 

1 

3 



2 

27 

12 

23 

30 

4 

15 

10 

9 

25 

5 

8 





8 

4 

2 

9 

19 











11 

29 

6 

6 

9 



16 



15 



4 



3 



4 







Sums. 



53 



126 



402 



Days. 
31 

8 
24 
31 

9 
18 
28 
31 


17 
31 
11 

6 
29 



8 
11 
22 
31 
14 
25 

2 

2 
18 
29 

6 
31 
12 


18 

3 
10 
21 
31 
28 

1 

6 
25 
26 
22 

4 





Days. 
11 
31 
31 
21 
13 
22 
31 
21 
'22 

9 
31 
23 
12 
24 

1 
18 
31 
17 
18 
21 
31 
11 
21 
27 

3 

14 
31 
20 
10 
21 
12 
28 
31 
31 
31 


20 


24 
26 
14 
18 
31 
31 

3 

5 

5 

24 
19 
31 



Days. 
22 
30 
30 

3 

8 

7 
30 
10 
19 
26 
30 
30 
25 
30 
30 
12 
30 
18 
24 
30 
30 


30 
30 
12 
30 
30 

2 
28 


17 
30 
25 
26 
30 
30 
30 
29 
30 
30 
12 
30 
22 
30 
14 
16 

1 
30 
30 
29 



740 



Days. 


27 
22 

2 
16 

1 
30 

5 
23 
25 
24 
17 

4 
27 

6 

8 
16 

4 
25 
14 

6 
30 


30 


17 
30 






21 
30 
18 
30 
30 

1 
19 


30 
23 
29 
27 
23 
30 



8 

2 

30 
29 
30 



Days. 


23 
6 


11 


15 


1 

25 

19 

3 

7 


7 
3 

6 


12 



31 





18 
2 

11 

23 




15 
9 



21 

30 




26 

23 

lii 



Days. 

76 

150 

17.8 

90 

82 

88 

166 

93 

88 

111 

216 

180 

94 

181 

87 

85 

131 

100 

171 

130 

138 

70 

77 

156 

74 

100 

196 

76 

62 

39 

104 

147 

117 

173 

207 

61 

113 

85 

156 

169 

' 105 

135 

138 

164 

44 

59 

26 

164 

141 

137 



981 1,127 1,205 819 363 5,930 



Table No. 12. 



A correlation is here shown between the precipitation for August, 
September, and October and the number of days that the river was 
below 10 feet at Cincinnati, during the same months, for each year of 
the entire 50 years. This is the usual correlation table. In these 
tables the correlation coefficient "r" is determined hj dividing the 
sum of column 8 by the square root of the product of the sums of 



28 



columns 4 and 7. If the correlation coefficient be 1 in this calcula- 
tion, there is an exact relation between the two factors, and if — 1 
there is an exact opposite connection. In this case 426.74x26,562 
(the sums of columns 4 and 7, respectively) = 11,335,067.88. The 
square root of this product is 3,366.76. The sum of column 8 is 
-2,490.8. This sum divided by 3,366.76= -0.74. This is a Very 
high negative coefficient and shows plainly that the smaller the 
amount of rainfall during August, September, and October the 
greater the number of days with the river below 10 feet. 

It is considered safe to assume that there is a well-defined relation 
in these cases if " r" is six times the probable error. The probable error 

1 — r 2 
is obtained by the following formula: 0.674 'i^r- In which "r" is 

the correlation coefficient and N the number of years under discussion. 
The probable error here is ±0.04, or only one-eighteenth of u r." 

The question might properly be raised as to whether the rainfall 
during July might have a marked influence on the low-water days in 
August, September, and October, as discussed in this table. But a 
similar correlation table worked out for the rainfall for July, August, 
September, and October, and the number of days with the river below 
10 feet in August, September, and October, gives a correlation coeffi- 
cient of —0.73, or very slightly less than with July rainfall omitted. 

Table 12.- — Correlation of precipitation and days with river below 10 feet, in August, 
September, and October, Ohio River, Cincinnati, Ohio, 1861 to 1910, inclusive. 



Years. 



Precipitation. 



Precipi- 
tation. 



Depart- 
ure. 



Square 
of col- 
umn 3. 



Days. 



Days. 



Depart- 
ure. 



Square 
of col- 
umn 6. 



Product 
of col- 
umns 3 
and 6. 



1861. 
1862. 
1863. 
1864. 
1865. 
1866. 
1867. 
1868. 
1869. 
1870. 
1871. 
1872. 
1873. 
1874. 
1875. 
1876. 
1877. 
1878. 
1879. 
1880. 
1881. 
1882. 
1883. 
1884. 
1885. 
1886. 
1887. 



Inches. 

11.4 
5.0 
8.7 

12.7 

10.2 

17.2 
6.6 

13.9 
8.2 
7.4 
7.5 
7.2 

10.6 
5.6 
7.8 

11.5 
5.9 

10.1 
9.7 
9.5 
8.8 

10.1 
9.3 
6.8 

12.0 

'8.1 
5.4 

14.3 
7.4 



Inches. 
+2.7 
-3.7 

+ 4.0 
+ 1.5 
+8.5 
-2.1 
+5.2 
-0.5 
-1.3 
-1.2 
-1.5 
+ 1.9 
-3.1 
-0.9 
+2.8 
-2.8 
+ 1.4 
+ 1.0 
+0.8 
+0.1 
+ 1.4 
+0.6 
-1.9 
+3.3 
-0.6 
-3.3 
+5.6 
-1.3 



Bays. 
33 
92 
92 
33 
46 
34 
92 
51 
65 
66 
92 



Days. 
-33 
+26 
+26 
-33 
-20 
-32 
+26 
-15 

- 1 


+26 
+ 18 

- 5 
+ 19 

- 4 
-19 
+26 

- 5 
+ 7 
+ 16 
+26 
-34 
+ 9 
+22 
-34 
+ 9 
+26 
-33 

- 4 



1,089 

676 

676 

1,089 

400 

1,024 

676 

225 

1 



676 

324 

25 

364 

16 

361 

676 

25 

49 

256 

676 

1,156 

81 

284 

1,156 

81 

676 

1,089 

16 



89.2 

96.2 



132.0 

30.0 

272.0 

54.6 

7S.0 

0.5 



31.2 

27.0 

9.5 

58.9 

3.6 

53.2 

72.8 

7.0 

7.0 

12.8 

2.6 

47.6 

5.4 

41.8 

112.2 

5.4 

85.8 

184.8 

5.2 



29 



Table 12. — Correlation of precipitation and days with river below 10 feet in August, 
September, and October, Ohio River, Cincinnati Ohio, 1861 to 1910, inclusive — 
Continued. 





Precipitation. 


Days. 


Product 


Years. 


Precipi- 
tation. 


Depart- 
ure. 


Square 
of col- 
umn 3. 


Days. 


Depart- 
ure. 


Square 
of col- 
umn 6. 


of col- 
umns 3 
and 6. 


1 


2 


3 


4 


5 


6 


7 


8 


1890 


Inches. 

14.6 
6.5 
6.5 
8.7 
7.2 
5.1 

10.3 
3.8 

10.9 
7.3 
6.8 
6.4 
7.5 
5.5 
4.7 

12.5 

10.9 
7.7 
4.3 
7.1 

10.4 


Inches. 
+5.9 
-2.2 
-2.2 

—1.5 
-3.6 
+ 1.6 
-4.9 
+2.2 
-1.4 
-1.9 
-2.3 
-1.2 
-3.2 
-4.0 
+3.8 
+2.2 
-1.0 
-4.4 
-1.6 
+ 1.7 


34.81 

4.84 

4.84 



2.25 

12.96 

2.56 

24.01 

4.84 

1.96 

3.61 

5.29 

1.44 

10.24 

16.00 

14.44 

4.84 

10.00 

19.36 

2.56 

2.89 


Days. 
21 

60 
89 
71 
8S 
92 
32 
81 
51 
85 
86 
57 
75 
80 
92 
36 
21 
24 
85 
79 
84 


Days. 
-45 

- 6 
+23 
+ 5 
+22 
+26 
-34 
+15 
-15 
+ 19 
+20 

- 9 
+ 9 
+ 14 
+26 
-30 
-45 
-42 
+ 19 
+ 13 
+ 18 


2,025 

36 

529 

25 

484 

676 

.1, 156 

225 

225 

361 

400 

81 

81 

196 

676 

900 

2,025 

1,764 

361 

169 

324 


- 265.5 


1891 ,.-. 

1892 


+ 13.2 
- 50.6 


1893 





1894... 


- 33.0 


1895 


- 93. 6 


1896 


- 54.4 


1897 


- 73.5 


1S98 


- 33.0 


1899 


- 26.6 


1900 


- 38.0 


1901 


+ 20.7 


1902 


- 10.8 


1903 


- 44.8 


1904 


— 104.0 


1905 .- 


— 114. 


1906 


- 99.0 


1907 


+ 42.0 


190S 


- 83.6 


1909 


- 20.8 


1910 


+ 30.6 












426. 74 






26,562 


-2, 490. 8 




8.7 




66 















The correlation coefficient is —0.74. The probable error is ±0.04. 

Table 13. 

In Table 13 the correlation coefficient is determined for the precipi- 
tation over the Ohio watershed above Cincinnati, and the number 
of days that the river was above 40 feet at Cincinnati, during the 
months of February and March, for the 50 years. The effect of the 
precipitation upon the flood conditions is more remarkable, if pos- 
sible, than upon the low-water days as indicated in Table 12, because 
the correlation coefficient is 0.80 in Table 13. This is 27 times the 
probable error. This table alone should be very conclusive evidence 
that the high-water conditions in the Ohio Valley, during the months 
when there are the greatest number of high-water days, are controlled 
by the precipitation and nothing else. 

By obtaining the correlation coefficient for the different 25-year 
periods from this table the fact that the cutting off of the forests does 
not make increased flood conditions is plainly established. The 
correlation coefficient for the 25 years from 1861 to 1885, inclusive, 
is 0.805, and for the 25 years from 1886 to 1910, inclusive, is 0.804, a 
difference much less than the probable error. This means that the 
tendency to cause the water to rise above 40 feet by the same precip- 
itation has been no greater during the last 25 years than during the 
preceding 25 years, or at least by a value too small to be calculated 
by the most approved method of correlation. 



30 

Table 13. — Precipitation and days with river above 40 feet in February and March, Ohio 
River, Cincinnati, Ohio, 1861 to 1910, inclusive. 



Years. 



Precipitation. 



Precipi- 
tation. 



Depart- 
ure. 



Square 
of col- 
umn 3. 



Days. 



Days. 



Depart- 
ure. 



Square 
of col- 
umn 6. 



Product 
of col- 
umns 3 
and 6. 



1861. 
1862. 
1863. 
1864. 
1865. 
1866. 
1867. 
1868. 
1869. 
1870. 
1871. 
1872. 
1873. 
1874. 
1875. 
1876. 
1877 . 
1878. 
1879. 
1880. 
1881. 
1882 . 
1883. 
1884. 
1885 . 
1886. 
1887. 
1888. 
1889. 
1890. 
1891. 
1892. 
1893. 
1894. 
1895 . 
1896. 
1897. 
1893. 
1899. 
1900. 
1901. 
1902. 
1903. 
1904. 
1905 . 
1906. 
1907. 
1905. 
1909. 
1910. 



Sums . 
Means. 



Inches. 
4.3 
7.7 
7.1 
4.0 
7.4 
6.2 
10.0 
6.5 
7.1 
7.3 
5.3 
3.4 
6.7 
7.6 
5.8 
6.3 
6.0 
4.7 
7.1 
8.0 
7.2 
10.1 
10.2 
10.2 
3.3 
5.1 
9.4 
6.1 
2.9 
12.3 
10.0 
6.1 
7.4 
5.9 
3.1 
6.7 
11.3 
9.3 
8.4 
5.4 
3.7 
4.2 
9.9 
8.0 
5.2 
6.9 
7.0 
10.6 
8.9 
7.3 



7.0 



Inches. 
-2.7 
+0.1 
+0.1 
-3.0 
+0.4 
-0.8 
+ 3.0 
-0.5 
+ 0.1 
+ 0.3 
-1.7 
-3.6 
-0.3 
+0.6 
-1.2 
-0.7 
—1.0 
-2.3 
+0.1 
+ 1.0 
+0.2 
+3.1 
+3.2 
+3.2 
-3.7 
-1.9 
+2.4 
-0.9 
-4.1 
+5.3 
+3.0 
-0.9 
+0.4 
-1.1 
-3.9 
-0.3 
+4.3 
+2.3 
+ 1.4 
-1.6 
-3.3 
-2.8 
+2.9 
+ 1.0 
-1.8 
-0.1 

+3.6 
+ 1.9 
+0.3 



7.29 

.49 

.01 

9.00 

.16 

.64 

9.00 

.25 

.01 

.09 

2.89 

12. 96 

.09 

.36 

1.44 

.49 

1.00 

5.92 

.01 

1.00 

.04 

9.61 

10.24 

10.24 

13.69 

3.61 

5.76 

.81 

16.81 

28.09 

9.00 

.81 

.16 

1.21 

15. 21 

.09 

18.49 

5.29 

1.96 

2.56 

10.89 

7.84 

8.41 

1.00 

3.21 

.01 



12.96 

3.61 

.09 



254. 80 



Days. 



16 

4 



21 



34 

10 

2 

2 





3 

5 

5 

11 

3 



2 

14 

9 

26 

18 

40 



2 

35 





37 

36 



14 







26 

10 

13 

/ 



17 

33 

14 

11 

1 

15 
28 
13 
13 



-11 
+ 5 

- 7 
-11 
+ 10 
-11 
+23 

- 1 

- 9 

- 9 
-11 
-11 

- 8 

- 6 

- 6 


- 8 
-11 

- 9 
+ 5 

- 2 
+ 15 
+ 7 
+29 
-11 

- 9 
+24 
-11 
-11 
+26 
+25 
-11 
+ 3 
-11 

- 11 
-11 
+15 

- 1 
+ 2 
-11 
-11 
+ 6 
+22 
+ 3 


-10 
+ 4 
+ 17 
+ 2 
+ 2 



121 

25 

49 

121 

100 

121 

529 

1 

81 

81 

121 

121 

64 

36 

36 



64 

121 

81 

25 

4 

225 

49 

841 

121 

81 

576 

121 

121 

676 

625 

121 

9 

121 

121 

121 

225 

] 

4 

121 

121 

36 

484 

9 



100 

16 

289 

4 

4 



7,245 



29.7 

0.5 

0.7 

33.0 

4.0 

8.8 

69.0 

0.5 

0.9 

2.7 

18.7 

39.6 

2.4 

3.6 

7.2 



8.0 

25.3 

0.9 

5.0 

0.4 

46.5 

22.4 

92.8 

40.7 

17.1 

57.6 

9.9 

45.1 

137.8 

75.0 

9.9 

1.2 

12.1 

42.9 

3.3 

64.5 

2.3 

2.8 

17.6 

36.3 

16.8 

63.8 

3.0 



1.0 



61.2 

3.8 

0.6 



+ 1,092.3 



The correlation coefficient is 0.80. The probable error is ±0.03. 

Table 14. 



In this table the same calculation is made for the relation between 
the precipitation in February and March and the number of days 
above 50 feet, or flood stage. One would not expect this correlation 
coefficient to be so high as in Table 13, even if the relation is actually 
closer, because of the great number of years when the river did not 



31 

rise above 50 feet during these two months. And yet in tins case 
"r" equals 0.74; high enough to make the relation well marked. 
The determination of the correlation coefficient in this table for each 
of the 25-year periods shows that the tendency to produce flood days 
with the same rainfall is slightly less during the last 25 years than 
during the preceding, although by a value too small to be considered, 
being about 0.3 per cent. 

Table 14. — Precipitation and days loith river above 50 feet in February and March, Ohio 
River, Cincinnati, Ohio, 1861 to 1910, inclusive. 



Years. 



Precipitation. 



Precipi- Depar- 
tation. ture. 



Square of 
column 3. 



Days. 



Days. 



Depar- 
ture. 



Square of 
column 6. 



Product 
of col- 
umns 

3 and 6. 



1861. 
1862. 
1863. 
1864. 
1865. 
1866. 
1867. 
1868. 
1869. 
1870. 
1871. 
1872. 
1873. 
1874. 
1875. 
1876. 
1877. 
1878. 
1879. 
1880. 
1881. 
1882. 
1883. 
1884. 
1885. 
1886. 
1887. 
1888. 
1889. 
1890. 
1891. 
1892. 
1893. 
1894. 
1895. 
1896. 
1897. 
1898. 
1899. 
1900. 
1901. 
1902. 
1903. 
1904. 
1905. 
1906. 
1907. 
1908. 
1909. 
1910. 



Inches. 
4.3 
7.7 
7.1 
4.0 
7.4 
6.2 
10.0 
6.5 
7.1 
7.3 
5.3 
3.4 
6.7 
7.6 
5.8 
6.3 
6.0 
4.7 
7.1 
8.0 
7.2 
10.1 
10.2 
10.2 
3.3 
5.1 
9.4 
6.1 
2.9 
12.3 
10.0 
6.1 
7.4 
5.9 
3.1 
6.7 
11.3 
9.3 
8.4 
5.4 
3.7 
4.2 
9.9 
8.0 
5.2 
6.9 
7.0 
10.6 
8.9 
7.3 



Inches. 
-2.7 
+0.7 
+0.1 
-3.0 
+ 0.4 
-0.8 
+3.0 
-0.5 
+0.1 
+0.3 
-1.7 
-3.6 
-0.3 
+0.6 
-1.2 
-0.7 
-1.0 
-2.3 
+0.1 
+ 1.0 
+0.2 
+3.1 
+3.2 
+3.2 
-3.7 
-1.9 
+2.4 
-0.9 
-4.1 
+5.3 
+3.0 
-0.9 
+0.4 
-1.1 
-3.9 
-0.3 
+ 4.3 
+2.3 
+ 1.4 
-1.6 
-3.3 
-2.8 
+2.9 
+ 1.0 
-1.8 
-0.1 

+3.6 
+ 1.9 
+0.3 



Sum.. 
Mean. 



7.0 



7.29 

.49 

.01 

9.00 

.16 

.64 

9.00 

.25 

.01 

.09 

2.89 

12.96 

.09 

.36 

1.44 

.49 

1.00 

5.92 

.01 

1.00 

.04 

9.61 

10.24 

10.24 

13.69 

3.61 

5.76 

.81 

16.81 

28.09 

9.00 

.81 

.16 

1.21 

15. 21 

.09 

18.49 

5.29 

1.96 

2.56 

10.89 

7.84 

S.41 

1.00 

3.21 

.01 



12. 96 

3.61 

.09 



Days. 




5 

19 












4 
2 

9 
16 

19 



13 



15 
8 

8 



8 



254. 80 



Days. 

- 4 

- 4 

- 4 

- 4 
+ 1 

- 4 
+ 15 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 

- 4 


- 2 
+ 5 
+ 12 
+ 15 

- 4 

- 4 
+ 9 

- 4 

- 4 
+ 11 
+ 4 

- 4 
+ 4 

- 4 

- 4 

- 4 
+ 4 
+ 3 
+ 3 

- 4 

- 4 


+ 4 

- 4 

- 4 

- 4 
+ 7 
+ 4 
+ 2 



16 

16 

16 

16 

1 

16 

225 

16 

16 

16 

16 

16 

16 

16 

16 

16 

16 

16 

16 



4 

25 

144 

225 

16 

16 

81 

16 

16 

121 

16 

16 

16 

16 

16 

16 

16 

9 

9 

16 

16 



16 

16 

16 

16 

49 

16 

4 

1 



+ 10. S 
-2.8 
-0.4 
+ 12.0 
+ 0.4 
+ 3.2 
+ 45.0 
+ 2.0 
-0.4 
- 1.2 

6.8 
14.4 

1.2 



+ 



+ 



2.4 
4.8 
+ 2.8 
+ 4.0 
+ 9.2 

- 0.4 



- 0.4 
+ 15.5 
+ 38.4 
+ 48.0 
+ 14.8 
+ 7.6 
+ 21.6 
+ 3.6 
+ 16.4 
+ 58.3 
+ 12.0 
+ 3.6 
+ 1.-6 
+ 4.4 
+ 15.6 
+ 1.2 
+ 17.2 
+ 6.9 
+ 4.2 
+ 6.4 
+ 13.2 


+ 11.6 
-4.0 
+ 7.3 
+ 0.4 


+ 14.4 
+ 3.8 
-0.3 



1,458 



+ 452.3 



The correlation coefficient is 0.74. 



32 



Table 15. 

In this table the years, precipitation, and river stages are grouped 
for each difference in precipitation amounting to 1 inch for February 
and March. This table shows several important facts, among them 
being : 

(1) In only one year has the river reached the flood stage during 
these months when the precipitation was less than the normal, 7 
inches. 

(2) The most marked ■ increase in flood days comes with the 
increase of the precipitation from between 9 and 1 inches to between 
10 and 11 inches. 

(3) The average rate of increase in number of flood days with each 
increase of 1 inch in the precipitation is 2.5; this calculation is made 
for years when the precipitation was above 7 inches. 

Table 15. — Precipitation and days with river above 50 feet in February and March, 
Ohio River, Cincinnati, Ohio, 1861 to 1910, inclusive. 



Precipitation between — 



Years. 



Precipi- 
tation. 



Days. 



Change. 



2.9 and 3.9 inches . 



4 and 4.9 inches . 



5 and 5.9 inches . 



6 and 6.9 inches. 



7 and 7.9 inches . 



Mean 

8 and 8.9 inches. 



Mean. 



1872 
1885 
1889 
1895 
1901 
1861 
1864 
1878 
1902 
1871 
1875 
1886 
1894 
1900 
1905 
1866 
1868 
1873 
1876 
1877 
1888 
1892 
1896 
1906 
1862 
1863 
1865 
1869 
1870 
1874 
1879 
1881 
1893 
1907 
1910 



1880 
1899 
1904 
1906 



3.4 
3.3 
2.9 
3.1 
3.7 
4.3 
4.0 
4.7 
4.2 
5.3 
5.8 
5.1 
5.9 
5.4 
5.2 
6.2 
6.5 
6.7 
6.3 
6.0 
6.1 
6.1 
6.7 
6.9 
7.7 
7.1 
7.4 
7.1 
7.3 
7.6 
7.1 
7.2 
7.4 
7.0 
7.3 



8.0 
8.4 
8.0 



33 



Table 15. — Precipitation and days with river above 50 feet in February and March, 
Ohio River, Cincinnati, Ohio, 1861 to 1910, inclusive — Continued. 



Precicipitatiou between — 


Years. 


Precipi- 
tation. 


Days. 


Change. 




1887 
1898 
1903 


9.4 
9.3 
9.9 


13 

7 
8 




















9 


4 










1867 


10.0 
10.1 
10.2 
10.2 
10.0 
10.6 


19 

9 
16 
19 

8 
8 






1882 
1883 
1884 
1891 
1908 




























13 


4 




1890 
1897 








12.3 
11.3 


15 

8 
















12 


—1 












2.5 













Table No. 16. 



This table groups the data when the rainfall was above the normal 
for February and March, by 10-year and 25-year periods, and shows 
plainly that instead of a tendency toward increase of flood days in 
recent years there is actually a decrease, with the same precipitation. 

As shown by the last sentence in the discussion of Table 15, the 
average increase in flood days is 2.5 with each increase in precipita- 
tion of 1 inch. Then if 8.2 inches of rain from 1861 to 1885, inclu- 
sive, caused 6.5 flood days each year, the rainfall of 9.2 inches from 
1886 to 1910, inclusive, should have caused 2.5 days more or 9 flood 
days each year. But, because the tendency to flood conditions is 
less, the increase of 1 inch of rain produced an increase of only 1.6 
flood days per year. 

Applying the same average increase of 2.5 days for each increase 
of 1 inch in rainfall, or 0.25 day for each increase of 0.1 inch of rain, 
it will be seen that the number of flood days in the 10 years, 1901 to 
1910, inclusive, is exactly the same as the flood days in the 10, years, 
1861 lo 1870, inclusive, if the difference in rainfall is taken into con- 
sideration, and is 2.75 days less than was produced in the 10 years, 
1881 to 1890, inclusive, after making alloAvance for the difference in 
rainfall. 



34 



Table 16. — Precipitation and days with river above 50 feet during February and March, 
by 10-year periods, Ohio River, Cincinnati, Ohio, 1861-1910, inclusive. 



Year. 


Year. 


Precipi- 
tation. 


Days. 


1861 to 1870, inclusive 


1862 
1863 
1865 
1869 
1870 
1867 


7.7 
7.1 
7.4 
7.1 
7.3 
10.0 








5 


19 




7.8 


4 




1874 
1879 
1880 




1871 to 1880, inclusive 


7.6 
7.1 
8.0 








4 


Mean 


7.6 


1 




1881 

1887 
1882 
1883 
1884 
1890 




1881 to 1890, inclusive '. 


7.2 
9.4 
10.1 
10.2 
10.2 
12.3 


2 




13 
9 
16 
19 
15 




9.9 


12 




1893 
1899 
1898 
1891 
1897 




1891 to 1900, inclusive 


7.4 
S.4 
9.3 
10.0 
11.3 


8 




7 
7 

I 


Mean 


9.3 


8 




1910 

1907 
1904 
1906 
1903 
1908 




1901 to 1910, inclusive 


7.3 
7.0 
8.0 
8.9 
9.9 
10.6 


3 




11 

9 

8 
8 




8.6 


6 








Mean, 1861 to 1885, inclusive 


8.2 
9.2 


6.5 


Mean, 1886 to 1910, inclusive 




8.1 









Table No. 17. 

In Table 17 the average rainfall and average number of days with 
the river below 10 feet in August, September, and October is tabu- 
lated for differences in rainfall amounting to 1 inch. This shows that 
the average increase in low-water days with each decrease of 1 inch 
of rain is 7. 

Table 17. — Average precipitation and days with river below 10 feet for August, Septem- 
ber, and October for each inch of rain, Ohio River, Cincinnati, Ohio, 1861 to 1910, 
inclusive. 



Precipitation — 


Mean 
precipi- 
tation. 


Mean 
days. 


Change. 




4.3 
5.4 
6.6 
7.4 
8.5 
9.5 
10.4 
13.3 


86 
89 
79 
72 
79 
77 
49 
36 






+ 3 




-10 




- 7 




+ 7 




- 2 




-28 




-13 












- 7 











6b 

Table No. 18. 

In Table 18 the average rainfall and average number of days with 
the water' below 10 feet in August, September, and October is given 
for each 10-year and each 25-year period. Remembering that the 
increase in low- water days amounts to an average of 7 a year with 
each decrease in the rainfall of 1 inch, it will be seen at once that the 
number of low-water days during the 10 years from 1901 to 1910, 
inclusive, were less than in any of the preceding 10-year periods, 
taking into the account the difference in rainfall. Also that during 
the last 25 years the average number of low-water days is 9.1 less 
than would have been produced in the first 25 years with the same 
amount of rainfall. Or, the tendency to produce low-water conditions 
in the Ohio River has been 14 per cent less during the 25 years from 
1886 to 1910, inclusive, than during the 25 years from 1861 to 1885, 
inclusive, with the same rainfall, as calculated during the low-water 
months of August, September, and October. 

Table 18. — Average precipitation and number of days with river below 10 feet for August , 
September, and October, by 10-year and 25-year periods, Ohio River, Cincinnati, Ohio, 
1861-1910, inclusive. 





Year. 


Precipi- 

> tation. 


Days. 


1861 to 1870 




10.1 


60 


1871 to 1880 




8.5 


74 


1881 to 1890 




9.7 


60 


1891 to 1900 




7.3 


74 


1901 to 1910 




7.7 


63 


1861 to 1885 




9.3 


66 


1886 to 1910 




S. 


60 











36 
Explanation op Chaets. 

Chart 1. — Indicates the location- of the seven precipitation stations 
that were used in obtaining the precipitation for the Ohio watershed 
above Cincinnati. 

Chart 2. — The influence of the rainfall upon the number of low- 
water days during the driest period of the year is plainly shown by 
this chart. 

Chart 3. — The relation between the precipitation and number of 
high- water days during the period of highest water is well indicated. 
Also that an equal amount of precipitation has no greater tendency 
to cause an increase in the number of high-water days during the 
latter part of the period than during the earlier part. 

Chart 4- — This chart shows that whenever the . precipitation for 
February and March was 1 inch or more above the normal the number 
of days with the water above 40 feet was always greater than the 
normal, with one exception. Also that when the precipitation was 
more than 2 inches above the normal, the number of days was much 
above the normal, with one or two exceptions. Further, that when 
the precipitation was below the normal the number of days was 
always less than the normal, with one exception. The line of dots 
on the — 11 days' line indicate no days with the river above 40 
feet, the average number of days being 11 per year. 



37 




Chart 1.— Location of precipitation stations. 



38 



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A. 







Chart 4.— Departures from normal precipitation during February and March and number of days 

with the river above 40 feet. 



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LIBRARY OF CONGRESS 



019 953 682 5 



